Carboxylate, carboxylic acid generator, resin, resist composition and method for producing resist pattern

ABSTRACT

A carboxylate represented by formula (I), a resin comprising a structural unit derived from the carboxylate represented by formula (I), a resit composition comprising the carboxylate represented by formula (I) or a resin comprising a structural unit derived from the carboxylate represented by formula (I).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C 119 to Japanese PatentApplication No. 2021-182467 filed on Nov. 9, 2021 and Japanese PatentApplication No. 2022-038538 filed on Mar. 11, 2022. Each of the aboveapplications is hereby expressly incorporated by reference, in itsentirety, into the present application.

FIELD

The present disclosure relates to a carboxylate, a carboxylic acidgenerator, a resin, a resist composition and a method for producing aresist pattern.

BACKGROUND ART

JP 2011-037834 A mentions a resist composition comprising a resinincluding a structural unit derived from a carboxylate represented bythe following formula.

The present disclosure provides a carboxylate forming a resist patternwith line edge roughness (LER) which is better than that of the aboveresist composition comprising a resin including a structural unitderived from a carboxylate.

SUMMARY

The present disclosure includes the following some embodiments.

Some embodiments are a salt represented by formula (I) and a resincomprising a structural unit represented by formula (IP):

wherein, in formula (I),

R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ each independently represent a halogen atom, ahaloalkyl group having 1 to 12 carbon atoms or a hydrocarbon grouphaving 1 to 18 carbon atoms, wherein each of the hydrocarbon group mayhave a substituent, and a —CH₂— included in each of the haloalkyl groupand the hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO₂—,

A¹, A² and A³ each independently represent a hydrocarbon group having 1to 20 carbon atoms, wherein each of the hydrocarbon group may have asubstituent, and a —CH₂-included in each of the hydrocarbon group may bereplaced by —O—, —CO—, —S— or —SO₂—,

m1 represents an integer of 1 to 5, and when m1 is 2 or more, aplurality of groups in parentheses may be the same or different fromeach other,

m2 represents an integer of 0 to 5, and when m2 is 2 or more, aplurality of groups in parentheses may be the same or different fromeach other,

m3 represents an integer of 0 to 5, and when m3 is 2 or more, aplurality of groups in parentheses may be the same or different fromeach other,

m4 represents an integer of 0 to 5, and when m4 is 2 or more, aplurality of R⁴ may be the same or different from each other,

m5 represents an integer of 0 to 5, and when m5 is 2 or more, aplurality of R⁵ may be the same or different from each other,

m6 represents an integer of 0 to 5, and when m6 is 2 or more, aplurality of R⁶ may be the same or different from each other,

m7 represents an integer of 0 to 4, and when m7 is 2 or more, aplurality of R⁷ may be the same or different from each other,

m8 represents an integer of 0 to 5, and when m8 is 2 or more, aplurality of R⁸ may be the same or different from each other,

m9 represents an integer of 0 to 5, and when m9 is 2 or more, aplurality of R⁹ may be the same or different from each other,

in which 1≤m1+m7≤5, 0≤m2+m8≤5, 0≤m3+m9≤5,

X⁰ represents a single bond or a hydrocarbon group having 1 to 72 carbonatoms which may have a substituent, and a —CH₂— included in thehydrocarbon group may be replaced by —O—, —S—, —CO— or —SO₂—,

Ph represents a phenylene group which may have a substituent,

Ax represents a single bond, an ether bond, an ester bond or a carbonicacid ester bond,

Ay represents a single bond, an ether bond, an ester bond or a carbonicacid ester bond,

* represents a bonding site to carbon atoms to which —R^(bb1) is bonded,

** represents a bonding site to L¹⁰, and

L¹⁰ represents a single bond or a hydrocarbon group having 1 to 36carbon atoms which may have a substituent, and a —CH₂— included in thehydrocarbon group may be replaced by —O—, —S—, —SO₂— or —CO—.

Some embodiments are resist compositions comprising a salt representedby above formula (I).

Some embodiments are resist compositions comprising a resin including astructural unit represented by above formula (IP).

Some embodiments are methods for producing a resist pattern, whichcomprises:

(1) a step of applying the resist compositions comprising the saltrepresented by formula (I) and/or the resin including a structural unitrepresented by above formula (IP).

DETAILED DESCRIPTION

In the present specification, “(meth)acrylic monomer” means “at leastone of acrylic monomer and methacrylic monomer”. Notations such as“(meth)acrylate” and “(meth)acrylic acid” have the same meaning. Ingroups mentioned in the present specification, regarding groups capableof having both a linear structure and a branched structure, they mayhave either the linear or branched structure. When —CH₂— included in thehydrocarbon group or the like is replaced by —O—, —S—, —CO— or —SO₂—,the same examples shall apply for each group. “Combined group” means agroup in which two or more exemplified groups are bonded, and valencesof those groups may be appropriately varied by bonding forms. “Derived”means that a polymerizable C═C bond included in the molecule becomes a—C—C— group (single bond) by polymerization. When stereoisomers exist,all stereoisomers are included.

In the present specification, “solid component of the resistcomposition” means the total amount of components in which thebelow-mentioned solvent (E) is removed from the total amount of theresist composition.

[Carboxylate Represented by Formula (I)]

The present disclosure relates to a carboxylate represented by formula(I) (hereinafter sometimes referred to as “salt (I)”).

Of the salt (I), the side having negative charge is sometimes referredto as “anion (I)”, and the side having positive charge is sometimesreferred to as “cation (I)”.

[Cation (I)]

The cation (I) of the salt represented by formula (I) is a cationrepresented by formula (I-C).

wherein, in formula (I-C), all symbols are the same as defined informula (I).

Examples of the halogen atom as for R⁴, R³, R⁶, R⁷, R⁸ and R⁹ include afluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The haloalkyl group having 1 to 12 carbon atoms as for R⁴, R⁵, R⁶, R⁷,R⁸ and R⁹ represents an alkyl group having 1 to 12 carbon atoms whichhas a halogen atom, and examples thereof include an alkyl fluoride grouphaving 1 to 12 carbon atoms, an alkyl chloride group having 1 to 12carbon atoms, an alkyl bromide group having 1 to 12 carbon atoms, analkyl iodide group having 1 to 12 carbon atoms and the like. Examples ofthe haloalkyl group include a perfluoroalkyl group having 1 to 12 carbonatoms (a trifluoromethyl group, a pentafluoroethyl group, aheptafluoropropyl group, a nonafluorobutyl group, etc.), a2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, achloromethyl group, a bromomethyl group, a fluoromethyl group, adifluoromethyl group, a trifluoromethyl group, a perfluorobutyl groupand the like. In some embodiments, the number of carbon atoms of thehaloalkyl group is preferably 1 to 9, more preferably 1 to 4, and stillmore preferably 1 to 3.

Examples of the hydrocarbon group having 1 to 18 carbon atoms as for R⁴,R⁵, R⁶, R⁷, R⁸ and R⁹ include a chain hydrocarbon group such as an alkylgroup and alkanediyl group, an alicyclic hydrocarbon group, an aromatichydrocarbon group, and groups formed by combining these groups.

Examples of the alkyl group include a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group,a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a2-ethylhexyl group, an octyl group, a nonyl group, a decyl group, anundecyl group and a dodecyl group.

Example of the alkanediyl group included a linear or branched alkanediylgroup, liner alkanediyl group includes a methylene group, an ethylenegroup, a propane-1,3-diyl group, a butane-1,4-diyl group, apentane-1,5-diyl group and a hexane-1,6-diyl, a branched alkanediylgroup includes ethane-1,1-diyl group, propane-1,1-diyl group,propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group,2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group,pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group.

In some embodiments, the number of carbon atoms of the chain hydrocarbongroup is preferably 1 to 9, more preferably 1 to 6, still morepreferably 1 to 4, and yet more preferably 1 to 3.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic,and examples of the alicyclic hydrocarbon group include groups shownbelow. The bonding site can be any position in groups shown below.

In some embodiments, examples of the monocyclic alicyclic hydrocarbongroup include cycloalkyl groups such as a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptylgroup, a cyclooctyl group and a cyclodecyl group. In some embodiments,examples of the polycyclic alicyclic hydrocarbon group include adecahydronaphthyl group, an adamantyl group, a norbornyl group and thelike. In some embodiments, the number of carbon atoms of the alicyclichydrocarbon group is preferably 3 to 18, more preferably 3 to 16, andstill more preferably 3 to 12.

Examples of the aromatic hydrocarbon group include a phenyl group, anaphthyl group, a biphenyl group, an anthryl group, a phenanthryl group,a binaphthyl group and the like. The number of carbon atoms of thearomatic hydrocarbon group is preferably 6 to 18, more preferably 6 to14, and still more preferably 6 to 10.

Examples of the group formed by combining two or more groups selectedfrom chain hydrocarbon groups, alicyclic hydrocarbon groups, andaromatic hydrocarbon groups include groups formed by combining anaromatic hydrocarbon group with a chain hydrocarbon group (e.g., thearomatic hydrocarbon group-alkanediyl group-*, the alkyl group-aromatichydrocarbon group-*, and the alkyl group-aromatic hydrocarbongroup-alkanediyl group-*, wherein a —CH₂— included in the alkanediylgroup and the alkyl group may be replaced by —O—, —CO—, —S— or —SO₂—),groups formed by combining an alicyclic hydrocarbon group with a chainhydrocarbon group (e.g., the alicyclic hydrocarbon group-alkanediylgroup-*, the alkyl group-alicyclic hydrocarbon group-*, and the alkylgroup-alicyclic hydrocarbon group-alkanediyl group-*, wherein a —CH₂—included in the alkanediyl group and the alkyl group may be replaced by—O—, —CO—, —S— or —SO₂—) and groups formed by combining an aromatichydrocarbon group with an alicyclic hydrocarbon group (e.g., an aromatichydrocarbon group-alicyclic hydrocarbon group-*, an alicyclichydrocarbon group-aromatic hydrocarbon group-*). * represents a bondingsite.

Examples of the aromatic hydrocarbon group-alkanediyl group-* includearalkyl groups such as a benzyl group and a phenethyl group.

Examples of the alkyl group-aromatic hydrocarbon group-* include a tolylgroup, a xylyl group, a cumenyl group and the like.

Examples of the alicyclic hydrocarbon group-alkanediyl group-* includecycloalkylalkyl groups such as a cyclohexylmethyl group, acyclohexylethyl group, a 1-(adamantan-1-yl)methyl group and1-(adamantan-1-yl)-1-methylethyl group.

Examples of the alkyl group-alicyclic hydrocarbon group-* includecycloalkyl groups having an alkyl group, such as a methylcyclohexylgroup, a dimethylcyclohexyl group and a 2-alkyladamantan-2-yl group.

Examples of the aromatic hydrocarbon group-alicyclic hydrocarbon group-*include a phenylcyclohexyl group and the like.

Examples of the alicyclic hydrocarbon group-aromatic hydrocarbon group-*include a cyclohexylphenyl group and the like.

In the group formed by combining two or more groups selected from chainhydrocarbon groups, alicyclic hydrocarbon groups, and aromatichydrocarbon groups, two or more of alicyclic hydrocarbon groups,aromatic hydrocarbon groups and chain hydrocarbon groups may berespectively combined. Any group may be bonded to the benzene ring.

When a —CH₂— included in the haloalkyl group or hydrocarbon grouprepresented by R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ is replaced by —O—, —CO—, —S—or —SO₂—, the number of carbon atoms before replacement is taken as thetotal number of the haloalkyl group or hydrocarbon group. The number maybe either 1, or 2 or more.

Examples of the group in which a —CH₂— included in the haloalkyl groupand the hydrocarbon group is replaced by —O—, —CO—, —S— or —SO₂— includea hydroxy group (a group in which a —CH₂— included in the methyl groupis replaced by —O—), a carboxy group (a group in which a —CH₂—CH₂—included in the ethyl group is replaced by —O—CO—), a thiol group (agroup in which a —CH₂— included in the methyl group is replaced by —S—),an alkoxy group (a group in which a —CH₂— at any position included inthe alkyl group is replaced by —O—), an alkoxycarbonyl group (a group inwhich a —CH₂—CH₂— at any position included in the alkyl group isreplaced by —O—CO—), an alkylcarbonyl group (a group in which a —CH₂— atany position included in the alkyl group is replaced by —CO—), analkylcarbonyloxy group (a group in which a —CH₂—CH₂— at any positionincluded in the alkyl group is replaced by —CO—O—), an alkylthio group(a group in which a —CH₂— included in the alkyl group is replaced by—S—), an alkylsulfonyl group (a group in which a —CH₂— included in thealkyl group is replaced by —SO₂—), an oxy group (a group in which a—CH₂— at any position included in the methylene group is replaced by—O—), a carbonyl group (a group in which a —CH₂— at any positionincluded in the methylene group is replaced by —CO—), a thio group (agroup in which a —CH₂— at any position included in the methylene groupis replaced by —S—), a sulfonyl group (a group in which a —CH₂— at anyposition included in the methylene group is replaced by —SO₂—), analkanediyloxy group (a group in which a —CH₂— at any position includedin the alkanediyl group is replaced by —O—), an alkanediyloxycarbonylgroup (a group in which a —CH₂—CH₂— at any position included in thealkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (agroup in which a —CH₂— at any position included in the alkanediyl groupis replaced by —CO—), an alkanediylcarbonyloxy group (a group in which a—CH₂—CH₂— at any position included in the alkanediyl group is replacedby —CO—O—), an alkanediylthio group (a group in which a —CH₂— at anyposition included in the alkanediyl group is replaced by —S—), analkanediylsulfonyl group (a group in which a —CH₂— at any positionincluded in the alkanediyl group is replaced by —SO₂—), a cycloalkoxygroup, a cycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatichydrocarbon group-carbonyloxy group, an aromatic hydrocarbongroup-carbonyl group, an aromatic hydrocarbon group-oxy group, ahaloalkoxy group (a group in which a —CH₂— at any position included inthe haloalkyl group is replaced by —O—), a haloalkoxycarbonyl group (agroup in which a —CH₂—CH₂— at any position included in the haloalkylgroup is replaced by —O—CO—), a haloalkylcarbonyl group (a group inwhich a —CH₂— at any position included in the haloalkyl group isreplaced by —CO—), a haloalkylcarbonyloxy group (a group in which a—CH₂—CH₂— at any position included in the haloalkyl group is replaced by—CO—O—), and a group obtained by combining two or more of these groups.

Examples of the alkoxy group include alkoxy group having 1 to 17 carbonatoms, for example, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxygroup and the like. In some embodiments, the number of carbon atoms ofthe alkoxy group is preferably 1 to 11, more preferably 1 to 6, stillmore preferably 1 to 4, and yet more preferably 1 to 3.

The alkoxycarbonyl group, the alkylcarbonyl group and thealkylcarbonyloxy group represent a group in which a carbonyl group or acarbonyloxy group is bonded to the above-mentioned alkyl group or alkoxygroup.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groupshaving 2 to 17 carbon atoms, for example, a methoxycarbonyl group, anethoxycarbonyl group, a butoxycarbonyl group and the like, examples ofthe alkylcarbonyl group include alkylcarbonyl groups having 2 to 18carbon atoms, for example, an acetyl group, a propionyl group and abutyryl group, and examples of the alkylcarbonyloxy group includealkylcarbonyloxy groups having 2 to 17 carbon atoms, for example, anacetyloxy group, a propionyloxy group, a butyryloxy group and the like.Examples of the alkylthio group include alkylthio groups having 1 to 17carbon atoms, for example, a methylthio group, an ethylthio group, apropylthio group and the like. In some embodiments, the number of carbonatoms of the alkoxycarbonyl group is preferably 2 to 11, more preferably2 to 6, and still more preferably 2 to 4. In some embodiments, thenumber of carbon atoms of the alkylcarbonyl group is preferably 2 to 12,more preferably 2 to 6, and still more preferably 2 to 4. In someembodiments, the number of carbon atoms of the alkylcarbonyloxy group ispreferably 2 to 11, more preferably 2 to 6, and still more preferably 2to 4. In some embodiments, the number of carbon atoms of the alkylthiogroup is preferably 2 to 11, more preferably 2 to 6, and still morepreferably 2 to 4.

Examples of the alkylthio group include alkylthio groups having 1 to 17carbon atoms such as a methylthio group, an ethylthio group, apropylthio group, a butylthio group, a pentylthio group, a hexylthiogroup, an octylthio group, a 2-ethylhexylthio group, a nonylthio group,a decylthio group and an undecylthio group. In some embodiments, thenumber of carbon atoms of the alkylthio group is preferably 1 to 11,more preferably 1 to 6, still more preferably 1 to 4, and yet morepreferably 1 to 3.

Examples of the alkylsulfonyl group include alkylsulfonyl groups having1 to 17 carbon atoms such as a methylsulfonyl group, an ethylsulfonylgroup, a propylsulfonyl group, a butylsulfonyl group, a pentylsulfonylgroup, a hexylsulfonyl group, an octylsulfonyl group, a2-ethylhexylsulfonyl group, a nonylsulfonyl group, a decylsulfonyl groupand an undecylsulfonyl group. In some embodiments, the number of carbonatoms of the alkylsulfonyl group is preferably 1 to 6, more preferably 1to 4, and still more preferably 1 to 3.

Examples of the alkanediyloxy group include alkanediyloxy groups having1 to 17 carbon atoms, for example, a methyleneoxy group, an ethyleneoxygroup, a propanediyloxy group, a butanediyloxy group, a pentanediyloxygroup and the like. In some embodiments, the number of carbon atoms ofthe alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6,still more preferably 1 to 4, and yet more preferably 1 to 3.

Examples of the alkanediyloxycarbonyl group includealkanediyloxycarbonyl groups having 2 to 17 carbon atoms, for example, amethyleneoxycarbonyl group, an ethyleneoxycarbonyl group, apropanediyloxycarbonyl group, a butanediyloxycarbonyl group and thelike. Examples of the alkanediylcarbonyl group includealkanediylcarbonyl groups having 2 to 17 carbon atoms, for example, amethylenecarbonyl group, an ethylenecarbonyl group, apropanediylcarbonyl group, a butanediylcarbonyl group, apentanediylcarbonyl group and the like. Examples of thealkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having2 to 17 carbon atoms, for example, a methylenecarbonyloxy group, anethylenecarbonyloxy group, a propanediylcarbonyloxy group, abutanediylcarbonyloxy group and the like. In some embodiments, thenumber of carbon atoms of the alkanediyloxycarbonyl group is preferably2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yetmore preferably 2 or 3. In some embodiments, the number of carbon atomsof the alkanediylcarbonyl group is preferably 2 to 12, more preferably 2to 6, still more preferably 2 to 4, and yet more preferably 2 or 3. Insome embodiments, the number of carbon atoms of thealkanediylcarbonyloxy group is preferably 2 to 11, more preferably 2 to6, still more preferably 2 to 4, and yet more preferably 2 or 3.

Examples of the alkanediylthio group include alkanediylthio groupshaving 1 to 17 carbon atoms, for example, a methylenethio group, anethylenethio group, a propylenethio group and the like. In someembodiments, the number of carbon atoms of the alkanediylthio group ispreferably 1 to 11, more preferably 1 to 6, still more preferably 1 to4, and yet more preferably 1 to 3.

Examples of the alkanediylsulfonyl group include alkanediylsulfonylgroups having 1 to 18 carbon atoms, for example, a methylenesulfonylgroup, an ethylenesulfonyl group, a propylenesulfonyl group and thelike. In some embodiments, the number of carbon atoms of thealkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6,still more preferably 1 to 4, and yet more preferably 1 to 3.

Examples of the cycloalkoxy group include cycloalkoxy groups having 3 to17 carbon atoms, for example, a cyclohexyloxy group and the like.Examples of the cycloalkylalkoxy group include cycloalkylalkoxy groupshaving 4 to 18 carbon atoms, for example, a cyclohexylmethoxy group andthe like. Examples of the alkoxycarbonyloxy group includealkoxycarbonyloxy group having 2 to 16 carbon atoms, for example, abutoxycarbonyloxy group and the like. Examples of the aromatichydrocarbon group-carbonyloxy group include aromatic hydrocarbongroup-carbonyloxy group having 7 to 18 carbon atoms, for example, abenzoyloxy group and the like. Examples of the aromatic hydrocarbongroup-carbonyl group include aromatic hydrocarbon group-carbonyl groupshaving 7 to 18 carbon atoms, for example, a benzoyl group and the like.Examples of the aromatic hydrocarbon group-oxy group include aromatichydrocarbon group-oxy groups having 6 to 16 carbon atoms, for example, aphenyloxy group and the like.

Examples of the haloalkoxy group, the haloalkoxycarbonyl group, thehaloalkylcarbonyl group and the haloalkylcarbonyloxy group includehaloalkoxy groups having 1 to 12 carbon atoms, haloalkoxycarbonyl groupshaving 2 to 12 carbon atoms, haloalkylcarbonyl groups having 2 to 12carbon atoms and haloalkylcarbonyloxy groups having 2 to 12 carbonatoms, for example, groups in which one or more hydrogen atoms of theabove-mentioned groups are substituted with a halogen atom.

Examples of the group in which —CH₂— included in the alicyclichydrocarbon group is replaced by —O—, —CO—, —S— or —SO₂— include groupsshown below. The bonding site can be any position in groups shown below.

Examples of the substituent which may be possessed by the hydrocarbongroup as for R⁴, R³, R⁶, R⁷, R⁸ and R⁹ include a halogen atom and acyano group.

Examples of the halogen atom include the same groups as mentioned above.

The hydrocarbon group may have one substituent or a plurality ofsubstituents.

Examples of the hydrocarbon group as for A¹, A² and A³ include linear orbranched chain hydrocarbon groups (e.g., an alkanediyl group, etc.),monocyclic or polycyclic alicyclic hydrocarbon groups, aromatichydrocarbon groups and the like, and the hydrocarbon group may be groupsformed by combining two or more of these groups.

Examples of the chain hydrocarbon group include linear alkanediyl groupssuch as a methylene group, an ethylene group, a propane-1,3-diyl group,a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a heptane-1,7-diyl group, an octane-1,8-diyl group, anonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diylgroup, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, atetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, ahexadecane-1,16-diyl group and a heptadecane-1,17-diyl group; and

branched alkanediyl groups such as an ethane-1,1-diyl group, apropane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diylgroup, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

In some embodiments, the number of carbon atoms of the chain hydrocarbongroup is preferably 1 to 18, more preferably 1 to 12, still morepreferably 1 to 9, yet more preferably 1 to 6, further preferably 1 to4, and still further preferably 1 to 3.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic,and examples thereof include groups show below. The bonding site can beany position in groups shown below.

In some embodiments, thereof include monoclyclic alicyclic hydrocarbongroups includes cycloalkanediyl groups such as a cyclobutane-1,3-diylgroup, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and acyclooctane-1,5-diyl group; and

polycyclic alicyclic hydrocarbon groups includes a norbornane-1,4-diylgroup, a norbornane-2,5-diyl group, an adamantane-1,5-diyl group, anadamantane-2,6-diyl group, and spiro rings having a cycloalkyl group, anorbornyl group or an adamantyl group, and a cycloalkyl groupspiro-bonded to each of them, such as spirocyclohexane-1,2′cyclopentaneand spiroadamantane-2,3′-cyclopentane groups.

In some embodiments, the number of carbon atoms of the alicyclichydrocarbon group is preferably 3 to 18, more preferably 3 to 16, stillmore preferably 3 to 12, and yet more preferably 3 to 10.

Examples of the aromatic hydrocarbon group include aromatic hydrocarbongroups, for example, arylene groups such as a phenylene group, anaphthylene group, an anthrylene group, a biphenylene group and aphenanthrylene group. In some embodiments, the number of carbon atoms ofthe aromatic hydrocarbon group is preferably 6 to 18, more preferably 6to 14, and still more preferably 6 to 10.

Examples of the group formed by combining two or more groups selectedfrom chain hydrocarbon groups, alicyclic hydrocarbon groups, andaromatic hydrocarbon groups include groups formed by combining analicyclic hydrocarbon group with an alkanediyl group, groups formed bycombining an aromatic hydrocarbon group with an alkanediyl, and groupsformed by combining an alicyclic hydrocarbon group with an aromatichydrocarbon group. In combination, two or more of chain hydrocarbongroups, alicyclic hydrocarbon groups and aromatic hydrocarbon groups maybe respectively combined. Any group may be bonded to the benzene ring.

Examples of the group formed by combining an alicyclic hydrocarbon groupwith an alkanediyl group include a -divalent alicyclic hydrocarbongroup-alkanediyl group-, an -alkanediyl group-divalent alicyclichydrocarbon group-alkanediyl group-, an -alkanediyl group-divalentalicyclic hydrocarbon group- and the like.

Examples of the group formed by combining an aromatic hydrocarbon groupwith an alkanediyl group include a -divalent aromatic hydrocarbongroup-alkanediyl group-, an -alkanediyl group-divalent aromatichydrocarbon group-alkanediyl group-, an -alkanediyl group-divalentaromatic hydrocarbon group- and the like.

Examples of the group formed by combining an alicyclic hydrocarbon groupwith an aromatic hydrocarbon group include an -aromatic hydrocarbongroup-alicyclic hydrocarbon group-, an -alicyclic hydrocarbongroup-aromatic hydrocarbon group-, an -alicyclic hydrocarbongroup-aromatic hydrocarbon group-an alicyclic hydrocarbon group- and thelike.

In A¹, A² and A³, when a —CH₂— included in the hydrocarbon group isreplaced by —O—, —CO—, —S— or —SO₂—, the number of carbon atoms beforereplacement is taken as the total number of the hydrocarbon group. Thenumber may be either 1, or 2 or more, and is preferably 1 to 3.

Examples of the group in which a —CH₂— included in the hydrocarbon groupis replaced by —O—, —CO—, —S— or —SO₂-include a hydroxy group (a groupin which a —CH₂— included in the methyl group is replaced by —O—), acarboxy group (a group in which a —CH₂—CH₂— included in the ethyl groupis replaced by —O—CO—), a thiol group (a group in which a —CH₂— includedin the methyl group is replaced by —S—), an alkoxy group (a group inwhich a —CH₂— at any position included in the alkyl group is replaced by—O—), an alkoxycarbonyl group (a group in which a —CH₂—CH₂— at anyposition included in the alkyl group is replaced by —O—CO—), analkylcarbonyl group (a group in which a —CH₂— at any position includedin the alkyl group is replaced by —CO—), an alkylcarbonyloxy group (agroup in which a —CH₂—CH₂— at any position included in the alkyl groupis replaced by —CO—O—), an alkylthio group (a group in which a —CH₂— atany position included in the alkyl group is replaced by —S—),alkylsulfonyl group (a group in which a —CH₂— at any position includedin the alkyl group is replaced by —SO₂—), an oxy group (a group in whicha —CH₂— included in the methylene group is replaced by —O—), a carbonylgroup (a group in which a —CH₂— included in the methylene group isreplaced by —CO—), a thio group (a group in which a —CH₂— included inthe methylene group is replaced by —S—), a sulfonyl group (a group inwhich a —CH₂— included in the methylene group is replaced by —SO₂—), analkanediyloxy group (a group in which a —CH₂— at any position includedin the alkanediyl group is replaced by —O—), an alkanediyloxycarbonylgroup (a group in which a —CH₂—CH₂— at any position included in thealkanediyl group is replaced by —O—CO—), an alkanediylcarbonyl group (agroup in which a —CH₂— at any position included in the alkanediyl groupis replaced by —CO—), an alkanediylcarbonyloxy group (a group in which a—CH₂—CH₂— at any position included in the alkanediyl group is replacedby —CO—O—), an alkanediylsulfonyl group (a group in which a —CH₂— at anyposition included in the alkanediyl group is replaced by —SO₂—), analkanediylthio group (a group in which a —CH₂— at any position includedin the alkanediyl group is replaced by —S—), a cycloalkoxy group, acycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatichydrocarbon group-carbonyloxy group, a group obtained by combining twoor more groups of these groups, and the like.

Examples of the alkoxy group include alkoxy groups having 1 to 20 carbonatoms, for example, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxygroup and the like. The number of carbon atoms of the alkoxy group ispreferably 1 to 11, more preferably 1 to 6, still more preferably 1 to4, and yet more preferably 1 to 3.

The alkoxycarbonyl group, the alkylcarbonyl group and thealkylcarbonyloxy group represent a group in which a carbonyl group or acarbonyloxy group is bonded to the above-mentioned alkyl group or alkoxygroup.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groupshaving 2 to 20 carbon atoms, for example, a methoxycarbonyl group, anethoxycarbonyl group, a butoxycarbonyl group and the like. Examples ofthe alkylcarbonyl group include alkylcarbonyl groups having 2 to 20carbon atoms, for example, an acetyl group, a propionyl group and abutyryl group. Examples of the alkylcarbonyloxy group includealkylcarbonyloxy groups having 2 to 20 carbon atoms, for example, anacetyloxy group, a propionyloxy group, a butyryloxy group and the like.The number of carbon atoms of the alkoxycarbonyl group is preferably 2to 11, more preferably 2 to 6, still more preferably 2 to 4, and yetmore preferably 2 or 3. The number of carbon atoms of the alkylcarbonylgroup is preferably 2 to 12, more preferably 2 to 6, still morepreferably 2 to 4, and yet more preferably 2 or 3. The number of carbonatoms of the alkylcarbonyloxy group is preferably 2 to 11, morepreferably 2 to 6, still more preferably 2 to 4, and yet more preferably2 or 3.

Examples of the alkylthio group include alkylthio groups having 1 to 20carbon atoms, for example, a methylthio group, an ethylthio group, apropylthio group, a butylthio group and the like. The number of carbonatoms of the alkylthio group is preferably 1 to 11, more preferably 1 to6, still more preferably 1 to 4, and yet more preferably 1 to 3.

Examples of the alkylsulfonyl group include alkylsulfonyl groups having1 to 20 carbon atoms, for example, a methylsulfonyl group, anethylsulfonyl group, a propylsulfonyl group and the like. In someembodiments, the number of carbon atoms of the alkylsulfonyl group ispreferably 1 to 11, more preferably 1 to 6, still more preferably 1 to4, and yet more preferably 1 to 3.

Examples of the alkanediyloxy group include alkanediyloxy group having 1to 20 carbon atoms, for example, a methyleneoxy group, an ethyleneoxygroup, a propanediyloxy group, a butanediyloxy group, a pentanediyloxygroup and the like. In some embodiments, the number of carbon atoms ofthe alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6,still more preferably 1 to 4, and yet more preferably 1 to 3.

Examples of the alkanediyloxycarbonyl group includealkanediyloxycarbonyl groups having 2 to 20 carbon atoms, for example, amethyleneoxycarbonyl group, an ethyleneoxycarbonyl group, apropanediyloxycarbonyl group, a butanediyloxycarbonyl group and thelike. Examples of the alkanediylcarbonyl group includealkanediylcarbonyl groups having 2 to 20 carbon atoms, for example, amethylenecarbonyl group, an ethylenecarbonyl group, apropanediylcarbonyl group, a butanediylcarbonyl group, apentanediylcarbonyl group and the like. Examples of thealkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having2 to 20 carbon atoms, for example, a methylenecarbonyloxy group, anethylenecarbonyloxy group, a propanediylcarbonyloxy group, abutanediylcarbonyloxy group and the like. In some embodiments, thenumber of carbon atoms of the alkanediyloxycarbonyl group is preferably2 to 11, more preferably 2 to 6, still more preferably 2 to 4, and yetmore preferably 2 or 3. The number of carbon atoms of thealkanediylcarbonyl group is preferably 2 to 12, more preferably 2 to 6,still more preferably 2 to 4, and yet more preferably 2 or 3. The numberof carbon atoms of the alkanediylcarbonyloxy group is preferably 2 to11, more preferably 2 to 6, still more preferably 2 to 4, and yet morepreferably 2 or 3.

Examples of the alkanediylsulfonyl group include alkanediylsulfonylgroups having 1 to 20 carbon atoms, for example, a methylenesulfonylgroup, an ethylenesulfonyl group, a propylenesulfonyl group and thelike. In some embodiments, the number of carbon atoms of thealkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6,still more preferably 1 to 4, and yet more preferably 1 to 3.

Examples of the alkanediylthio group include alkanediylthio groupshaving 1 to 20 carbon atoms, for example, a methylenethio group, anethylenethio group, a propylenethio group and the like. In someembodiments, the number of carbon atoms of the alkanediylthio group ispreferably 1 to 11, more preferably 1 to 6, still more preferably 1 to4, and yet more preferably 1 to 3.

Examples of the cycloalkoxy group include cycloalkoxy group having 3 to20 carbon atoms, for example, a cyclohexyloxy group and the like.Examples of the cycloalkylalkoxy group include cycloalkylalkoxy groupshaving 4 to 17 carbon atoms, for example, a cyclohexylmethoxy group andthe like. Examples of the alkoxycarbonyloxy group includealkoxycarbonyloxy groups having 2 to 16 carbon atoms, for example, abutoxycarbonyloxy group and the like. Examples of the aromatichydrocarbon group-carbonyloxy group include aromatic hydrocarbongroup-carbonyloxy groups having 7 to 20 carbon atoms, for example, abenzoyloxy group and the like.

Examples of the group in which a —CH₂— included in the alicyclichydrocarbon group is replaced by —O—, —CO—, —S— or —SO₂— include groupsshown below. Examples of the group also include groups in which a —O— isreplaced by —S— and —CO— is replaced by —SO₂—, respectively, among thegroups shown below. The bonding site can be any position in groups shownbelow.

Examples of the substituent which may be possessed by the hydrocarbongroup as for A¹, A² and A³ include the same groups as mentioned for thesubstituent which may be possessed by the hydrocarbon group as for R⁴ toR⁹.

In some embodiments, it is preferable that A¹, A² and A³ are eachindependently a hydrocarbon group having 1 to 20 carbon atoms (thehydrocarbon group may have a substituent, and one of —CH₂— included inthe hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO₂—). Insome embodiments, it is more preferable that A¹ is ***-L⁰¹¹-X⁰¹-L⁰¹²-,A² is ***-L⁰²¹-X⁰²-L⁰²²-, and A³ is ***-L⁰³¹-X⁰³-L⁰³²-(X⁰¹, X⁰² and X⁰³each independently represent —O—, —CO—, —S— or —SO₂—, L⁰¹¹, L⁰¹², L⁰²¹,L⁰²², L⁰³¹ and L⁰³² each independently represent a single bond or ahydrocarbon group having 1 to 18 carbon atoms, in which the total numberof carbon atoms of L⁰¹¹ and L⁰¹² is 0 to 18, the total number of carbonatoms of L⁰²¹ and L⁰²² is 0 to 18, the total number of carbon atoms ofL⁰³¹ and L⁰³² is 0 to 18, and *** represents a bonding site to thebenzene ring to which S⁺ is bonded), and it is still more preferablethat A¹ is ***—X⁰¹-L⁰¹- or ***-L⁰¹-X⁰¹—, A² is ***—X⁰²-L⁰²- or***-L⁰²-X⁰²—, and A³ is ***—X⁰³-L⁰³- or ***-L⁰³-X⁰³—(X⁰¹, X⁰² and X⁰³each independently represent —O—, —CO—, —S— or —SO₂—, L⁰¹, L⁰² and L⁰³each independently represent a single bond or a hydrocarbon group having1 to 18 carbon atoms, and *** represents a bonding site to the benzenering to which S⁺ is bonded). In some embodiments, A¹, A² and A³ arepreferably those having no substituent, except for replacement by —O—,—CO—, —S— or —SO₂—.

Examples of the hydrocarbon group having 1 to 18 carbon atoms as forL⁰¹¹, L⁰¹², L⁰²¹, L⁰²², L⁰³¹, L⁰³², L⁰¹, L⁰² and L⁰³ (the hydrocarbongroup may have a substituent, and —CH₂— included in the hydrocarbongroup may be replaced by —O—, —CO—, —S— or —SO₂—) include the samegroups as mentioned for A¹, A² and A³ in the range of the number ofcarbon atoms of 1 to 18.

In some embodiments, X⁰¹, X⁰² and X⁰³ are each independently —O— or —S—,and preferably —O—.

In some embodiments, L⁰¹¹, L⁰¹², L⁰²¹, L⁰²², L⁰³¹, L⁰³², L⁰¹, L⁰² andL⁰³ are each independently a single bond, a hydrocarbon group having 1to 12 carbon atoms (a —CH₂-included in the hydrocarbon group may bereplaced by —O—, —CO—, —S— or —SO₂—), preferably a single bond, a chainhydrocarbon group having 1 to 9 carbon atoms (a —CH₂-included in thechain hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO₂—),more preferably a single bond, an alkanediyl group having 1 to 6 carbonatoms (a —CH₂— included in the alkanediyl group may be replaced by —O—or —CO—), yet more preferably a single bond, an alkanediyl group having1 to 4 carbon atoms (a —CH₂— included in the alkanediyl group may bereplaced by —O— or —CO—), and further preferably a single bond, analkanediyl group having 1 to 3 carbon atoms (a —CH₂— included in thealkanediyl group may be replaced by —O— or —CO—). Of these, a singlebond, a methylene group, an ethane-1,1-diyl group, a propane-1,1-diylgroup, a propane-2,2-diyl group, a carbonyl group, a carbonyloxy group,a carbonyloxymethylene group, an ethyleneoxy group, amethylenecarbonyloxymethylene group or an ethyleneoxycarbonyl group ispreferable, and a single bond, a methylene group or a carbonyl group ismore preferable.

In some embodiments, the bonding site of A¹, A² and A³ to the benzenering to which S⁺ is bond may be the o-position, the m-position or thep-position, with respect to the bonding site of S⁺. Particularly, theyare bonded preferably at the p-position or the m-position, with respectto the bonding site of S⁺. More specifically, when m1, m2 and m3 are 1,A¹, A² and A³ are each independently bonded preferably at the p-positionor the m-position, and more preferably at the p-position, with respectto the bonding site of S⁺. When m1, m2 and m3 are 2, it is preferablethat one of A¹, A² and A³ is each independently bonded at the o-positionor the m-position and one of them is each independently bonded at theo-position or the m-position, with respect to the bonding site of S⁺,and it is more preferable that two of A¹, A² and A³ are eachindependently bonded at the m-position, with respect to the bonding siteof S⁺. When m1, m2 and m3 are 3, it is preferable that two of A¹, A² andA³ are each independently bonded at the o-position or the m-position andone of them is each independently bonded at the p-position or them-position, with respect to the bonding site of S⁺, and it is morepreferable that two of A¹, A² and A³ are each independently bonded atthe m-position and one of them is each independently bonded at thep-position, with respect to the bonding site of S⁺. When m1, m2 and m3are 4, it is preferable that two of A¹, A² and A³ are each independentlybonded at the o-position or the m-position and two of them are eachindependently bonded at the p-position or the m-position, with respectto the bonding site of S⁺, and it is more preferable that two of A¹, A²and A³ are each independently bonded at the o-position and two of themare each independently bonded at the m-position, with respect to thebonding site of S⁺.

In some embodiments, m1 is preferably 1, 2, 3 or 4, more preferably 1, 2or 3, still more preferably 1 or 2, and yet more preferably 1.

In some embodiments, m2 is preferably 0, 1, 2, 3 or 4, more preferably0, 1, 2 or 3, still more preferably 0, 1 or 2, and yet more preferably 0or 1.

In some embodiments, m3 is preferably 0, 1, 2, 3 or 4, more preferably0, 1, 2 or 3, still more preferably 0, 1 or 2, yet more preferably 0 or1, and further preferably 0. In some embodiments, m4 is preferably 0, 1,2, 3 or 5, and more preferably 0, 1, 2 or 5.

In some embodiments, m5 is preferably 0 or 1, and more preferably 0.

In some embodiments, m6 is preferably 0 or 1, and more preferably 0. m7is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and still morepreferably 0.

In some embodiments, m8 is preferably 0, 1, 2 or 3, more preferably 0, 1or 2, and still more preferably 0 or 1.

In some embodiments, m9 is preferably 0, 1, 2 or 3, more preferably 0, 1or 2, and still more preferably 0 or 1.

In some embodiments, when m1 is 2 or more, or when m2 and m3 are 1 ormore, a plurality of groups in parentheses may be the same or differentfrom each other, that is, when there are a plurality of X¹ to X³, andwhen there are a plurality of R⁴ to R⁶, these groups may be the same ordifferent from each other.

R⁴, R⁵ and R⁶ each independently represent a halogen atom, an alkylfluoride group having 1 to 4 carbon atoms or an alkyl group having 1 to6 carbon atoms (—CH₂— included in the alkyl group may be replaced by —O—or —CO—), more preferably a halogen atom, an alkyl fluoride group having1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms (a—CH₂— included in the alkyl group may be replaced by —O— or —CO—), stillmore preferably a fluorine atom, an iodine atom, a perfluoroalkyl grouphaving 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms(a —CH₂-included in the alkyl group may be replaced by —O— or —CO—), andyet more preferably a fluorine atom, an iodine atom or a trifluoromethylgroup.

In some embodiments, the bonding site of R⁴, R³ and R⁶ to the benzenering may be each independently the o-position, the m-position or thep-position with respect to the bonding site of A¹, A² and A³.Particularly, when m4, m5 and m6 are 1, R⁴, R⁵ and R⁶ are eachindependently bonded preferably at the p-position or the m-position, andmore preferably at the p-position, with respect to the bonding site ofA¹, A² and A³. When m4, m5 and m6 are 2, it is preferable that one ofR⁴, R⁵ and R⁶ is each independently bonded at the o-position or them-position and one of them is each independently bonded at thep-position or the m-position, with respect to the bonding site of A¹, A²and A³, and it is more preferable that two of R⁴, R⁵ and R⁶ are eachindependently bonded at the m-position, with respect to the bonding siteof A¹, A² and A³. When m4, m5 and m6 are 3, it is preferable that two ofR⁴, R⁵ and R⁶ are each independently bonded at the p-position or them-position and one of them is each independently bonded at thep-position or the m-position, with respect to the bonding site of A¹, A²and A³, and it is more preferable that two of R⁴, R³ and R⁶ are eachindependently bonded at the m-position and one of them is eachindependently bonded at the p-position, with respect to the bonding siteof A¹, A² and A³. When m4, m5 and m6 are 4, it is preferable that two ofR⁴, R³ and R⁶ are each independently bonded at the o-position or them-position and two of them are each independently bonded at thep-position or the m-position, with respect to the bonding site of A¹, A²and A³, and it is more preferable that two of R⁴, R³ and R⁶ are eachindependently bonded at the m-position, one of them is eachindependently bonded at the o-position and one of them is eachindependently bonded at the p-position, with respect to the bonding siteof A¹, A² and A³.

In some embodiments, R⁷, R⁸ and R⁹ are each independently preferably ahalogen atom, an alkyl fluoride group having 1 to 4 carbon atoms or analkyl group having 1 to 6 carbon atoms (—CH₂— included in the alkylgroup may be replaced by —O— or —CO—), more preferably a halogen atom,an alkyl fluoride group having 1 to 4 carbon atoms or an alkyl grouphaving 1 to 4 carbon atoms (—CH₂— included in the alkyl group may bereplaced by —O— or —CO—), still more preferably a fluorine atom, aniodine atom, a perfluoroalkyl group having 1 to 4 carbon atoms or analkyl group having 1 to 4 carbon atoms (—CH₂— included in the alkylgroup may be replaced by —O— or —CO—), and yet more preferably afluorine atom, an iodine atom or a trifluoromethyl group.

In some embodiments, he bonding site of R⁷, R⁸ and R⁹ to the benzenering may be each independently the o-position, the m-position or thep-position with respect to the bonding site of S⁺. Particularly, whenm7, m8 and m9 are 1, R⁷, R⁸ and R⁹ are each independently bondedpreferably at the p-position or the m-position, and more preferably atthe p-position, with respect to the bonding site of S⁺. When m7, m8 andm9 are 2, it is preferable that one of R⁷, R⁸ and R⁹ is eachindependently bonded at the o-position or the m-position and one of themis each independently bonded at the p-position or the m-position, withrespect to the bonding site of S⁺, and it is more preferable that one ofR⁷, R⁸ and R⁹ is each independently bonded at the m-position and one ofthem is each independently bonded at the p-position, with respect to thebonding site of S⁺. When m7, m8 and m9 are 3, it is preferable that twoof R⁷, R⁸ and R⁹ are each independently bonded at the o-position or them-position and one of them is each independently bonded at thep-position or the m-position, with respect to the bonding site of S⁺,and it is more preferable that two of R⁷, R⁸ and R⁹ are eachindependently bonded at the m-position and one of them is eachindependently bonded at the p-position, with respect to the bonding siteof S⁺. When m7, m8 and m9 are 4, it is preferable that two of R⁷, R⁸ andR⁹ are each independently bonded at the o-position or the m-position andtwo of them are each independently bonded at the p-position or them-position, with respect to the bonding site of S⁺, and it is morepreferable that two of R⁷, R⁸ and R⁹ are each independently bonded atthe m-position, one of them is each independently bonded at theo-position and one of them is each independently bonded at thep-position, with respect to the bonding site of S⁺.

In some embodiments, examples of the cation (I) represented by formula(I-C) include a cation represented by formula (I-C-1) (hereinaftersometimes referred to as “cation (I-C-1)”):

wherein, in formula (I-C-1),

symbols R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, m1, m2, m3, m4, m5, m6, m7,m8, m9, L⁰¹, L⁰², L⁰³, X⁰¹, X⁰² and X⁰³ are the same as defined above.

X⁰¹, X⁰² and X⁰³ are preferably —O—.

The bonding site of X⁰¹, X⁰² and X⁰³ to the benzene ring is respectivelythe same bonding site of A¹, A² and A³ to the benzene ring.

Examples of the cation of the salt (I) include cations represented bythe following formula (I-c-1) to formula (I-c-44).

[Anion (I)]

The anion (I) of a salt represented by formula (I) is an anionrepresented by formula (I-A):

wherein, in formula (I-A), all symbols are the same as defined informula (I).

Examples of the hydrocarbon group represented by X⁰ in formula (I-A)include aliphatic hydrocarbon groups (chain hydrocarbon groups andalicyclic hydrocarbon groups, such as an alkanediyl group, an alkenediylgroup and an alkynediyl group), aromatic hydrocarbon groups, and a groupobtained by combining these groups. —CH₂— included in the aliphatichydrocarbon group may be replaced by —O—, —S—, —CO— or —SO₂—.

Examples of the alkanediyl group include linear alkanediyl groups suchas a methylene group, an ethylene group, a propane-1,3-diyl group, abutane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a heptane-1,7-diyl group, an octane-1,8-diyl group, anonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diylgroup and a dodecane-1,12-diyl group; and

branched alkanediyl groups such as an ethane-1,1-diyl group, apropane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diylgroup, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

Examples of the alkenediyl group include an ethenediyl group, apropenediyl group, an isopropenediyl group, a butenediyl group, anisobutenediyl group, a tert-butenediyl group, a pentenediyl group, ahexenediyl group, a heptenediyl group, an octanediyl group, anisooctanediyl group and a nonenediyl group.

Examples of the alkynedyl group include an ethynediyl group, apropynediyl group, an isopropynediyl group, a butynediyl group, anisobutynediyl group, a tert-butynediyl group, a pentynediyl group, ahexynediyl group, an octynediyl group, a nonynediyl group and the like.

Examples of the group in which —CH₂— included in the chain hydrocarbongroup is replaced by —O—, —S—, —CO— or —SO₂— include a hydroxy group (agroup in which —CH₂— included in the methyl group is replaced by —O—), acarboxy group (a group in which —CH₂—CH₂— included in the ethyl group isreplaced by —O—CO—), a thiol group (a group in which —CH₂-included inthe methyl group is replaced by —S—), an alkoxy group (a group in which—CH₂— at any position included in the alkyl group is replaced by —O—),an alkoxycarbonyl group (a group in which —CH₂—CH₂— at any positionincluded in the alkyl group is replaced by —O—CO—), an alkylcarbonylgroup (a group in which —CH₂— at any position included in the alkylgroup is replaced by —CO—), an alkylcarbonyloxy group (a group in which—CH₂—CH₂— at any position included in the alkyl group is replaced by—CO—O—), an alkylthio group (a group in which —CH₂— at any positionincluded in the alkyl group is replaced by —S—) and the like.

Examples of the alkoxy group, the alkoxycarbonyl group, the sulfidegroup, the alkylcarbonyl group, the alkylcarbonyloxy group and thealkylthio group include the same groups as mentioned above.

Replacement in the alkenediyl group and the alkynediyl group may bethose including a carbon-carbon double bond or a carbon-carbon triplebond at any position in exemplification of the replacement in theabove-mentioned alkyl group.

The alicyclic hydrocarbon group may be monocyclic, polycyclic or spiroring. Examples of the divalent alicyclic hydrocarbon group includegroups shown below. The bonding site can be any position in groups shownbelow.

Specifically, examples of the monocyclic divalent alicyclic hydrocarbongroup include monocyclic cycloalkanediyl groups such as acyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, acyclohexane-1,4-diyl group, a cyclohexene-3,6-diyl group and acyclooctane-1,5-diyl group, and examples of the polycyclic divalentalicyclic hydrocarbon group include polycyclic cycloalkanediyl groupssuch as a norbornane-1,4-diyl group, a norbornane-2,5-diyl group, a5-norbornene-2,3-diyl group, an adamantane-1,5-diyl group and anadamantane-2,6-diyl group.

The number of carbon atoms of the divalent alicyclic hydrocarbon groupis preferably 3 to 18, more preferably 3 to 16, and still morepreferably 3 to 12.

Specifically, examples of the group in which —CH₂-included in thealicyclic hydrocarbon group or the alicyclic hydrocarbon group isreplaced by —O—, —S—, —CO— or —SO₂-include the following groups. Thebonding site can be any position in groups shown below.

The group in which —CH₂— included in the alicyclic hydrocarbon group orthe alicyclic hydrocarbon group is replaced by —O—, —S—, —CO— or —SO₂—is preferably groups represented by formulas (y1) to (y71), morepreferably a group represented by any one of formula (y1) to formula(y20), formula (y26), formula (y27), formula (y30), formula (y31) andformula (y39) to formula (y71), and still more preferably groupsrepresented by formula (y3), formula (y4), formula (y9), formula (y11),formula (y14), formula (y15), formula (y16), formula (y20), formula(y26), formula (y27), formula (y30), formula (y31), formula (y39),formula (y40), formula (y42), formula (y43), formula (y49) to formula(y58) and formula (y62) to formula (y71). The number of carbon atoms ofthe alicyclic hydrocarbon group is preferably 3 to 36, more preferably 3to 24, still more preferably 3 to 18, yet more preferably 3 to 16, andfurther preferably 3 to 12.

Examples of the aromatic hydrocarbon group include a phenylene group, anaphthylene group, an anthrylene group, a biphenylene group, aphenanthrylene group and the like. The number of carbon atoms of thearomatic hydrocarbon group is preferably 6 to 18, more preferably 6 to14, and still more preferably 6 to 10.

Examples of the hydrocarbon group obtained by combining two or moregroups include groups obtained by combining an alkanediyl group, analicyclic hydrocarbon group and/or an aromatic hydrocarbon groups, suchas an -alicyclic hydrocarbon group-alkanediyl group-, an -alkanediylgroup-alicyclic hydrocarbon group-, an -alkanediyl group-alicyclichydrocarbon group-alkanediyl group-, an -alkanediyl group-aromatichydrocarbon group-, an -aromatic hydrocarbon group-alkanediyl group- andthe like.

When —CH₂— included in the hydrocarbon group represented by X⁰ isreplaced by —O—, —S—, —CO— or —SO₂—, the number of carbon atoms beforereplacement is taken as the total number of carbon atoms of thehydrocarbon group. When the substituent is bonded to the hydrocarbongroup represented by X⁰, the number of carbon atoms before replacementis taken as the total number of carbon atoms of the hydrocarbon group.

The hydrocarbon group represented by X⁰ may have one or a plurality ofsubstituents.

Examples of the substituent include a hydroxy group, a halogen atom, acyano group, an alkyl group having 1 to 12 carbon atoms, an alkoxy grouphaving 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, analkylcarbonyloxy group having 2 to 13 carbon atoms, an alicyclichydrocarbon group having 3 to 12 carbon atoms, an aromatic hydrocarbongroup having 6 to 10 carbon atoms, or a group obtained by combiningthese groups.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

Examples of the alkyl group having 1 to 12 carbon atoms include a methylgroup, an ethyl group, a propyl group, an isopropyl group, a butylgroup, an isobutyl group, a tert-butyl group, a pentyl group, a hexylgroup, an octyl group, a nonyl group and the like.

Examples of the alkoxy group having 1 to 12 carbon atoms include amethoxy group, an ethoxy group, a propoxy group, a butoxy group, apentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxygroup, a nonyloxy group, a decyloxy group, an undecyloxy group, adodecyloxy group and the like.

The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonylgroup having 2 to 13 carbon atoms and the alkylcarbonyloxy group having2 to 13 carbon atoms represent groups in which a carbonyl group or acarbonyloxy group is bonded to the above-mentioned alkyl group or alkoxygroup.

Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms includea methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl groupand the like, examples of the alkylcarbonyl group having 2 to 13 carbonatoms include an acetyl group, a propionyl group and a butyryl group,and examples of the alkylcarbonyloxy group having 2 to 13 carbon atomsinclude an acetyloxy group, a propionyloxy group, a butyryloxy group andthe like.

Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atomsinclude groups shown below. ** represents a bonding site to X⁰.

Examples of the aromatic hydrocarbon group having 6 to 10 carbon atomsinclude aryl groups such as a phenyl group and a naphthyl group.

Examples of the combined group include a group obtained by combining ahydroxy group with an alkyl group having 1 to 12 carbon atoms, a groupobtained by combining an alkyl group having 1 to 12 carbon atoms with anaromatic hydrocarbon group having 6 to 10 carbon atoms, a group obtainedby combining an alicyclic hydrocarbon group having 3 to 12 carbon atomswith an aromatic hydrocarbon group having 6 to 10 carbon atoms and thelike.

Examples of the group obtained by combining a hydroxy group with analkyl group having 1 to 12 carbon atoms include hydroxyalkyl groupshaving 1 to 12 carbon atoms, such as a hydroxymethyl group and ahydroxyethyl group.

Examples of the group obtained by combining an alkyl group having 1 to12 carbon atoms with an aromatic hydrocarbon group having 6 to 10 carbonatoms include aralkyl groups having 7 to 22 carbon atoms such as abenzyl group, and alkylaryl groups having 7 to 22 carbon atoms such as atolyl group and a xylyl group.

Examples of the group obtained by combining an alicyclic hydrocarbongroup having 3 to 12 carbon atoms with an aromatic hydrocarbon grouphaving 6 to 10 carbon atoms include cyclohexylphenyl groups and thelike.

The hydrocarbon group represented by X⁰ is preferably an aliphatichydrocarbon group having 1 to 72 carbon atoms which may have asubstituent (—CH₂— included in the aliphatic hydrocarbon group may bereplaced by —O—, —S—, —CO— or —SO₂—), or an aromatic hydrocarbon grouphaving 6 to 36 carbon atoms which may have a substituent,

more preferably an alicyclic hydrocarbon group having 3 to 36 carbonatoms which may have a substituent (in which a —CH₂— included in thealicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or —SO₂),a group obtained by combining an alicyclic hydrocarbon group having 3 to36 carbon atoms which may have a substituent with a chain hydrocarbongroup having 1 to 18 carbon atoms which may have a substituent (a —CH₂—included in the alicyclic hydrocarbon group may be replaced by —O—, —S—,—CO— or —SO₂—, and a —CH₂-included in the chain hydrocarbon group may bereplaced by —O— or —CO—), or a group obtained by combining an aromatichydrocarbon group having 6 to 36 carbon atoms which may have asubstituent or an aromatic hydrocarbon group having 6 to 36 carbon atomswhich may have a substituent with a chain hydrocarbon group having 1 to18 carbon atoms which may have a substituent,

still more preferably an *-alicyclic hydrocarbon group (a —CH₂— includedin the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or—SO₂—, the alicyclic hydrocarbon group may have a hydroxy group or afluorine atom, and * represents a bonding site to carbon atoms of—COO⁻), an *-alicyclic hydrocarbon group-chain hydrocarbon group (a—CH₂— included in the alicyclic hydrocarbon group may be replaced by—O—, —S—, —CO— or —SO₂—, a —CH₂— included in the chain hydrocarbon groupmay be replaced by —O— or —CO—, the alicyclic hydrocarbon group and thechain hydrocarbon group may have a fluorine atom or a hydroxy group,and * represents a bonding site to carbon atoms of —COO⁻), a *-chainhydrocarbon group-alicyclic hydrocarbon group (a —CH₂— included in thechain hydrocarbon group may be replaced by —O— or —CO—, a —CH₂— includedin the alicyclic hydrocarbon group may be replaced by —O—, —S—, —CO— or—SO₂—, the chain hydrocarbon group and the alicyclic hydrocarbon groupmay have a fluorine atom or a hydroxy group, and * represents a bondingsite to carbon atoms of —COO⁻), an *-aromatic hydrocarbon group (thearomatic hydrocarbon group may have a fluorine atom or a hydroxy group,and * represents a bonding site to carbon atoms of —COO⁻), or a *-chainhydrocarbon group-aromatic hydrocarbon group (a —CH₂-included in thechain hydrocarbon group may be replaced by —O— or —CO—, the chainhydrocarbon group and the aromatic hydrocarbon group may have a fluorineatom or a hydroxy group, and * represents a bonding site to carbon atomsof —COO⁻), and

yet more preferably a *-monocyclic alicyclic hydrocarbon group (—CH₂—included in the alicyclic hydrocarbon group may be replaced by —O—, —S—,—CO— or —SO₂—), a *-polycyclic alicyclic hydrocarbon group (a—CH₂-included in the polycyclic alicyclic hydrocarbon group may bereplaced by —O—, —S—, —CO— or —SO₂—, the polycyclic alicyclichydrocarbon group may be spiro ring, the polycyclic alicyclichydrocarbon group may have a hydroxy group or a fluorine atom, and *represents a bonding site to carbon atoms of —COO⁻), a *-polycyclicalicyclic hydrocarbon group-chain hydrocarbon group (a —CH₂— included inthe polycyclic alicyclic hydrocarbon group may be replaced by —O—, —S—,—CO— or —SO₂—, —CH₂— included in the chain hydrocarbon group may bereplaced by —O— or —CO—, the polycyclic alicyclic hydrocarbon group andthe chain hydrocarbon group may have a fluorine atom or a hydroxy group,and * represents a bonding site to carbon atoms of —COO⁻), a *-chainhydrocarbon group-polycyclic alicyclic hydrocarbon group (a —CH₂—included in the chain hydrocarbon group may be replaced by —O— or —CO—,—CH₂— included in the polycyclic alicyclic hydrocarbon group may bereplaced by —O—, —S—, —CO— or —SO₂—, the chain hydrocarbon group and thepolycyclic alicyclic hydrocarbon group may have a fluorine atom or ahydroxy group, and * represents a bonding site to carbon atoms of—COO⁻), or an aromatic hydrocarbon group which may have a fluorine atomor a hydroxy group.

In the above groups, the number of carbon atoms of the alicyclichydrocarbon group is preferably 3 to 36, more preferably 3 to 24, stillmore preferably 3 to 18, yet more preferably 3 to 16, and furtherpreferably 3 to 12. The number of carbon atoms of the chain hydrocarbongroup is preferably 1 to 18, more preferably 1 to 12, still morepreferably 1 to 9, yet more preferably 1 to 6, and further preferably 1to 4. The number of carbon atoms of the aromatic hydrocarbon group ispreferably 6 to 36, more preferably 6 to 24, still more preferably 6 to18, yet more preferably 6 to 14, and further preferably 6 to 10.

In the above groups, the number of carbon atoms of the chain hydrocarbongroup is preferably 1 to 6.

The above monocyclic alicyclic hydrocarbon group is a cycloalkanediylgroup having 5 or 6 carbon atoms (—CH₂-included in the cycloalkanediylgroup may be replaced by —O— or —CO—, and the cycloalkanediyl group maybe an acetal ring), the above polycyclic alicyclic hydrocarbon group isan adamandiyl group, a norbornanediyl group, or a polycyclic alicyclichydrocarbon group in which a cycloalkanediyl group having 5 or 6 carbonatoms and an adamantanediyl group are spiro-bonded, (a —CH₂— included inthe adamantanediyl group, the norbornanediyl group and thecycloalkanediyl group may be replaced by —O— or —CO—, a —CH₂—CH₂—included in the adamantanediyl group and norbornanediyl group may bereplaced by —O—CO—, and the cycloalkanediyl group may be an acetalring), and the above aromatic hydrocarbon group is a phenyl group.

In the above groups, the chain hydrocarbon group preferably has afluorine atom.

X⁰ is an alkanediyl group having 1 to 6 carbon atoms, a cycloalkanediylgroup having 5 or 6 carbon atoms, an adamantanediyl group, anorbornanediyl group, a phenylene group, a group obtained by combiningan alkanediyl group having 1 to 6 carbon atoms bonded to COO⁻ with thecycloalkanediyl group having 5 or 6 carbon atoms bonded to thealkanediyl group, the adamantanediyl group, the norbornanediyl group,the phenylene group, or a polycyclic alicyclic hydrocarbon group inwhich a cycloalkanediyl group having 5 or 6 carbon atoms and anadamantanediyl group are spiro-bonded, —CH₂— included in the alkanediylgroup, the cycloalkanediyl group, the adamantanediyl group and thenorbornanediyl group may be replaced by —O— or —CO—, —CH₂—CH₂— includedin the alkanediyl group, the adamantanediyl group and the norbornanediylgroup may be replaced by —O—CO— or —CO—O—, and one or more hydrogenatoms included in the alkanediyl group, the cycloalkanediyl group, theadamantanediyl group, the norbornanediyl group and phenyl group may besubstituted with a fluorine atom, a perfluoroalkyl group having 1 to 4carbon atoms, a hydroxy group or a methylhydroxy group.

X⁰ is particularly preferably an adamantanediyl group, ahydroxyadamantanediyl group, a group obtained by combining an alkanediylgroup having 1 to 6 carbon atoms bonded to COO⁻ with an adamantanediylgroup (—CH₂— included in the alkanediyl group may be replaced by —O— or—CO—), a phenylene group, or a phenylene group having a hydroxy group.

Examples of the halogen atom as for R^(bb1) include the same halogenatoms as mentioned for R⁴ to R⁹. Examples of the alkyl group which mayhave a halogen atom as for R^(bb1) include the same alkyl groups andhaloalkyl groups as mentioned for R⁴ to R⁹ as long as the upper limit ofthe number of carbon atoms permits.

R^(bb1) is preferably a hydrogen atom or a methyl group, and morepreferably a methyl group.

When X¹⁰ is a group represented by *-Ax-Ph-Ay-**, it is preferably alinking group represented by the following formula (X10).

In formula (X10), Ax represents bond species bonded to carbon atoms towhich R¹⁰ is bonded, and represents one bond species selected from thegroup consisting of a single bond, an ether bond, an ester bond and acarbonic acid ester bond.

Ay represents bond species bonded to L¹⁰, and represents one bondspecies selected from the group consisting of a single bond, an etherbond, an ester bond and a carbonic acid ester bond.

When either Ax or Ay is a single bond, the other is preferably oneselected from the group consisting of an ether bond, an ester bond and acarbonic acid ester bond.

Rx represents a halogen atom, a hydroxy group, an alkyl fluoride grouphaving 1 to 6 carbon atoms, an alkyl group having 1 to 18 carbon atomsor an alkoxy group having 1 to 6 carbon atoms. Of these, a fluorineatom, an iodine atom, a trifluoromethyl group, a methyl group or anethyl group is preferable.

mx represents an integer of 0 to 4, and preferably 0, 1 or 2. When mx isan integer of 2 or more, a plurality of Rx may be the same or differentfrom each other.

The bonding site of Ay in the phenylene group is preferably them-position or the p-position, and more preferably the p-position, withrespect to Ax.

In some embodiments, examples of X¹⁰ include groups represented by thefollowing formula (X¹-1), formula (X¹-2′) to formula (X¹-7′) and formula(X¹-8). * represents a bonding site to carbon atoms to which —R¹⁰ isbonded. ** represents a bonding site to L¹⁰.

Specific examples of the group represented by formula (X¹-2′) to formula(X¹-7′) include the following groups.

In some embodiments, X¹⁰ is preferably groups represented by formula(X¹-1) to formula (X¹-7), more preferably a group represented by formula(X¹-1), formula (X¹-3), formula (X¹-4) or formula (X¹-5), and still morepreferably a group represented by formula (X¹-1), a group represented byformula (X¹-4) or a group represented by formula (X¹-5).

The divalent hydrocarbon group having 1 to 36 carbon atoms as for L¹⁰includes divalent aliphatic hydrocarbon groups (divalent chainhydrocarbon groups and divalent alicyclic hydrocarbon groups, such as analkanediyl group, an alkenediyl group and an alkynedyl group), divalentaromatic hydrocarbon groups and the like, and may be divalenthydrocarbon groups obtained by combining two or more of these groups.

Examples of the alkanediyl group include linear alkanediyl groups suchas a methylene group, an ethylene group, a propane-1,3-diyl group, abutane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a heptane-1,7-diyl group, an octane-1,8-diyl group, anonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diylgroup and a dodecane-1,12-diyl group; and

branched alkanediyl groups such as an ethane-1,1-diyl group, apropane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diylgroup, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

Examples of the alkenediyl group include an ethenediyl group, apropenediyl group, an isopropenediyl group, a butenediyl group, anisobutenediyl group, a tert-butenediyl group, a pentenediyl group, ahexenediyl group, a heptenediyl group, an octanediyl group, anisooctanediyl group and a nonenediyl group.

Examples of the alkynedyl group include an ethynediyl group, apropynediyl group, an isopropynediyl group, a butynediyl group, anisobutynediyl group, a tert-butynediyl group, a pentynediyl group, ahexynediyl group, an octynediyl group, a nonynediyl group and the like.

In some embodiments, the number of carbon atoms of the chain hydrocarbongroup is preferably 1 to 12, more preferably 1 to 9, still morepreferably 1 to 6, yet more preferably 1 to 4, and further preferably 1to 3.

The divalent alicyclic hydrocarbon group may be monocyclic, polycyclicor spiro ring. Examples of the divalent alicyclic hydrocarbon groupinclude groups shown below. The bonding site can be any position ingroups shown below.

Specifically, examples of the monocyclic divalent alicyclic hydrocarbongroup include monocyclic cycloalkanediyl groups such as acyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, acyclohexane-1,4-diyl group, a cyclohexene-3,6-diyl group and acyclooctane-1,5-diyl group; and examples of the polycyclic divalentalicyclic hydrocarbon group include polycyclic cycloalkanediyl groupssuch as a norbornane-1,4-diyl group, a norbornane-2,5-diyl group, a5-norbornene-2,3-diyl group, an adamantane-1,5-diyl group and anadamantane-2,6-diyl group.

The number of carbon atoms of the divalent alicyclic hydrocarbon groupis preferably 3 to 18, more preferably 3 to 16, and still morepreferably 3 to 12.

Examples of the divalent aromatic hydrocarbon group include a phenylenegroup, a naphthylene group, an anthrylene group, a biphenylene group, aphenanthrylene group and the like. The number of carbon atoms of thearomatic hydrocarbon group is preferably 6 to 18, more preferably 6 to14, and still more preferably 6 to 10.

Examples of the hydrocarbon group obtained by combining two or moregroups include groups obtained by combining an alkanediyl group, analicyclic hydrocarbon group and/or an aromatic hydrocarbon group, andexamples thereof include an -alicyclic hydrocarbon group-alkanediylgroup-, an -alkanediyl group-alicyclic hydrocarbon group-, an-alkanediyl group-alicyclic hydrocarbon group-alkanediyl group-, an-alkanediyl group-aromatic hydrocarbon group-, an -aromatic hydrocarbongroup-alkanediyl group- and the like.

A —CH₂— included in the hydrocarbon group having 1 to 36 carbon atoms asfor L¹⁰ may be replaced by —O—, —S—, —CO— or —SO₂—.

When the hydrocarbon group having 1 to 36 carbon atoms as for L¹⁰ has asubstituent, or when a —CH₂— included in the hydrocarbon group isreplaced by —O—, —S—, —CO— or —SO₂—, the number of carbon atoms beforereplacement is taken as the number of carbon atoms of the hydrocarbongroup.

Examples of the group in which a —CH₂— included in the hydrocarbon groupis replaced by —O—, —S—, —SO₂— or —CO— include a hydroxy group (a groupin which a —CH₂— included in the methyl group is replaced by —O—), acarboxy group (a group in which a —CH₂—CH₂— included in the ethyl groupis replaced by —O—CO—), a thiol group (a group in which —CH₂-included inthe methyl group is replaced by —S—), an alkoxy group (a group in whicha —CH₂— at any position included in the alkyl group is replaced by —O—),an alkoxycarbonyl group (a group in which a —CH₂—CH₂— at any positionincluded in the alkyl group is replaced by —O—CO—), an alkylcarbonylgroup (a group in which a —CH₂— at any position included in the alkylgroup is replaced by —CO—), an alkylcarbonyloxy group (a group in whicha —CH₂—CH₂— at any position included in the alkyl group is replaced by—CO—O—), an alkanediyloxy group (a group in which a —CH₂— at anyposition included in the alkanediyl group is replaced by —O—), analkanediyloxycarbonyl group (a group in which a —CH₂—CH₂— at anyposition included in the alkanediyl group is replaced by —O—CO—), analkanediylcarbonyl group (a group in which a —CH₂— at any positionincluded in the alkanediyl group is replaced by —CO—), analkanediylcarbonyloxy group (a group in which a —CH₂—CH₂— at anyposition included in the alkanediyl group is replaced by —CO—O—), analkylthio group (a group in which a —CH₂— at any position included inthe alkyl group is replaced by —S—), an alkylsulfonyl group (a group inwhich a —CH₂— at any position included in the alkyl group is replaced by—SO₂—), a cycloalkoxy group, a cycloalkylalkoxy group, analkoxycarbonyloxy group, an aromatic hydrocarbon group-carbonyloxygroup, a group obtained by combining two or more of these groups and thelike.

Examples of the alkoxy group include alkoxy groups having 1 to 17 carbonatoms, for example, a methoxy group, an ethoxy group, a propoxy group, abutoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxygroup and the like. In some embodiments, he number of carbon atoms ofthe alkoxy group is preferably 1 to 11, more preferably 1 to 6, stillmore preferably 1 to 4 or 1 to 3.

The alkoxycarbonyl group, the alkylcarbonyl group and thealkylcarbonyloxy group represent a group in which a carbonyl group or acarbonyloxy group is bonded to the above-mentioned alkyl group or alkoxygroup.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groupshaving 2 to 17 carbon atoms, for example, a methoxycarbonyl group, anethoxycarbonyl group, a butoxycarbonyl group and the like. Examples ofthe alkylcarbonyl group include alkylcarbonyl groups having 2 to 18carbon atoms, for example, an acetyl group, a propionyl group and abutyryl group. Examples of the alkylcarbonyloxy group includealkylcarbonyloxy groups having 2 to 17 carbon atoms, for example, anacetyloxy group, a propionyloxy group, a butyryloxy group and the like.In some embodiments, the number of carbon atoms of the alkoxycarbonylgroup, the alkylcarbonyl group and the alkylcarbonyloxy group ispreferably 2 to 11, more preferably 2 to 6, still more preferably 2 to4, and yet more preferably 2 to 3.

Examples of the alkanediyloxy group include alkanediyloxy groups having1 to 17 carbon atoms, for example, a methyleneoxy group, an ethyleneoxygroup, a propanediyloxy group, a butanediyloxy group, a pentanediyloxygroup and the like.

Examples of the alkanediyloxycarbonyl group includealkanediyloxycarbonyl groups having 2 to 17 carbon atoms, for example, amethyleneoxycarbonyl group, an ethyleneoxycarbonyl group, apropanediyloxycarbonyl group, a butanediyloxycarbonyl group and thelike. Examples of the alkanediylcarbonyl group includealkanediylcarbonyl groups having 2 to 18 carbon atoms, for example, amethylenecarbonyl group, an ethylenecarbonyl group, apropanediylcarbonyl group, a butanediylcarbonyl group, apentanediylcarbonyl group and the like. Examples of thealkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having2 to 17 carbon atoms, for example, a methylenecarbonyloxy group, anethylenecarbonyloxy group, a propanediylcarbonyloxy group, abutanediylcarbonyloxy group and the like. In some embodiments, thenumber of carbon atoms of the alkanediyloxycarbonyl group, thealkanediylcarbonyl group and the alkanediylcarbonyloxy group ispreferably 2 to 11, more preferably 2 to 6, and still more preferably 2to 4 or 2 to 3.

Examples of the alkylthio group include alkylthio groups having 1 to 17carbon atoms, for example, a methylthio group, an ethylthio group, apropylthio group and the like. In some embodiments, the number of carbonatoms of the alkylthio group is preferably 1 to 11, more preferably 1 to6, and still more preferably 1 to 4 or 1 to 3.

Examples of the alkylsulfonyl group include alkylsulfonyl groups having1 to 17 carbon atoms, for example, a methylsulfonyl group, anethylsulfonyl group, a propylsulfonyl group and the like. In someembodiments, the number of carbon atoms of the alkylsulfonyl group ispreferably 1 to 11, more preferably 1 to 6, and still more preferably 1to 4 or 1 to 3.

Examples of the cycloalkoxy group include cycloalkoxy groups having 3 to17 carbon atoms, for example, a cyclohexyloxy group and the like.Examples of the cycloalkylalkoxy group include cycloalkylalkoxy groupshaving 4 to 17 carbon atoms, for example, a cyclohexylmethoxy group andthe like. Examples of the alkoxycarbonyloxy group includealkoxycarbonyloxy group having 2 to 16 carbon atoms, for example, abutoxycarbonyloxy group and the like. The number of carbon atoms of thecycloalkoxy group and the cycloalkylalkoxy group is preferably 3 to 11,and more preferably 3 to 6. In some embodiments, the number of carbonatoms of the alkoxycarbonyloxy group is preferably 2 to 11, morepreferably 2 to 6, still more preferably 2 to 4, and yet more preferably2 to 3. Examples of the aromatic hydrocarbon group-carbonyloxy groupinclude aromatic hydrocarbon group-carbonyloxy groups having 7 to 17carbon atoms, for example, a benzoyloxy group and the like.

Examples of the group in which —CH₂— included in the alicyclichydrocarbon group is replaced by —O—, —S—, —CO— or —SO₂— include thefollowing groups shown below. The position of —O— or —CO— of the groupsshown below may be respectively replaced by —S— or —SO₂—. The bondingsite can be any position in groups shown below.

Examples of the substituent which may be possessed by the hydrocarbongroup as for L¹⁰ include a halogen atom, a cyano group and the like.

By the group in which —CH₂— included in the hydrocarbon group as for L¹⁰is replaced by —O— or —CO—, L¹⁰ can substantially have a substituent ofa hydroxy group, a carboxy group, an alkoxy group, an alkoxycarbonylgroup, an alkylcarbonyl group or an alkylcarbonyloxy group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

The divalent hydrocarbon group having 1 to 36 carbon atoms as for L¹⁰may have one substituent or a plurality of substituents.

L¹⁰ is preferably a single bond, an alkanediyl group having 1 to 4carbon atoms (in which a —CH₂— included in the alkanediyl group may bereplaced by —O— or —CO—), an alicyclic hydrocarbon group having 3 to 18carbon atoms (in which a —CH₂— included in the alicyclic hydrocarbongroup may be replaced by —O—, —S—, —SO₂— or —CO—), a group obtained bycombining an aromatic hydrocarbon group having 6 to 18 carbon atomswhich may have a substituent, an alkanediyl group having 1 to 4 carbonatoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms (inwhich —CH₂— included in the alkanediyl group may be replaced by —O— or—CO—, and a —CH₂-included in the alicyclic hydrocarbon group may bereplaced by —O—, —S—, —SO₂— or —CO—) or a group obtained by combining analkanediyl group having 1 to 4 carbon atoms with an aromatic hydrocarbongroup having 6 to 18 carbon atoms which may have a substituent (a —CH₂—included in the alkanediyl group may be replaced by —O— or —CO—), morepreferably a single bond, an alkanediyl group having 1 to 4 carbon atoms(in which —CH₂— included in the alkanediyl group may be replaced by —O—or —CO—), an alicyclic hydrocarbon group having 3 to 18 carbon atoms (inwhich a —CH₂— included in the alicyclic hydrocarbon group may bereplaced by —O— or —CO—), a group obtained by combining a phenylenegroup which may have a substituent, an alkanediyl group having 1 to 4carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbonatoms (in which a —CH₂— included in the alkanediyl group may be replacedby —O— or —CO—, and —CH₂— included in the alicyclic hydrocarbon groupmay be replaced by —O— or —CO—) or a group obtained by combining analkanediyl group having 1 to 4 carbon atoms with a phenylene group whichmay have a substituent (in which a —CH₂— included in the alkanediylgroup may be replaced by —O— or —CO—), and still more preferably asingle bond or alkanediyl group having 1 to 4 carbon atoms (in which a—CH₂— included in the alkanediyl group may be replaced by —O— or —CO—).

Examples of the anion (I) include the following anions.

In some embodiments, examples of the carboxylate (I) include saltsobtained by optionally combining the above-mentioned cations and anions.Specific examples of the salt (I) are shown in the following table.

In the following table, the respective symbols represent symbolsimparted to structures showing the above-mentioned anions and cations,and “to” indicates that the salt (I) and the anion (I) correspond toeach other. For example, the carboxylate (I-1) indicates a salt composedof an anion represented by formula (I-a-1) and a cation represented byformula (I-c-1), the salt (I-2) indicates a salt composed of an anionrepresented by formula (I-a-2) and a cation represented by formula(I-c-1), and the salt (I-28) indicates a salt composed of an anionrepresented by formula (I-a-1) and a cation represented by formula(I-c-2).

TABLE 1 Carboxylate (I) Anion (I) Cation (I)  (I-1) to (I-27) (I-a-1) to(I-a-27) (I-c-1) (I-28) to (I-54) (I-a-1) to (I-a-27) (I-c-2) (I-55) to(I-81) (I-a-1) to (I-a-27) (I-c-3)  (I-82) to (I-108) (I-a-1) to(I-a-27) (I-c-4) (I-109) to (I-135) (I-a-1) to (I-a-27) (I-c-5) (I-136)to (I-162) (I-a-1) to (I-a-27) (I-c-6) (I-163) to (I-189) (I-a-1) to(I-a-27) (I-c-7) (I-190) to (I-216) (I-a-1) to (I-a-27) (I-c-8) (I-217)to (I-243) (I-a-1) to (I-a-27) (I-c-9) (I-244) to (I-270) (I-a-1) to(I-a-27) (I-c-10) (I-271) to (I-297) (I-a-1) to (I-a-27) (I-c-11)(I-298) to (I-324) (I-a-1) to (I-a-27) (I-c-12) (I-325) to (I-351)(I-a-1) to (I-a-27) (I-c-13) (I-352) to (I-378) (I-a-1) to (I-a-27)(I-c-14) (I-379) to (I-405) (I-a-1) to (I-a-27) (I-c-15) (I-406) to(I-432) (I-a-1) to (I-a-27) (I-c-16) (I-433) to (I-459) (I-a-1) to(I-a-27) (I-c-17) (I-460) to (I-486) (I-a-1) to (I-a-27) (I-c-18)(I-487) to (I-513) (I-a-1) to (I-a-27) (I-c-19) (I-514) to (I-540)(I-a-1) to (I-a-27) (I-c-20) (I-541) to (I-567) (I-a-1) to (I-a-27)(I-c-21) (I-568) to (I-594) (I-a-1) to (I-a-27) (I-c-22) (I-595) to(I-621) (I-a-1) to (I-a-27) (I-c-23) (I-622) to (I-648) (I-a-1) to(I-a-27) (I-c-24) (I-649) to (I-675) (I-a-1) to (I-a-27) (I-c-25)(I-676) to (I-702) (I-a-1) to (I-a-27) (I-c-26) (I-703) to (I-729)(I-a-1) to (I-a-27) (I-c-27) (I-730) to (I-756) (I-a-1) to (I-a-27)(I-c-28) (I-757) to (I-783) (I-a-1) to (I-a-27) (I-c-29) (I-784) to(I-810) (I-a-1) to (I-a-27) (I-c-30) (I-811) to (I-837) (I-a-1) to(I-a-27) (I-c-31) (I-838) to (I-864) (I-a-1) to (I-a-27) (I-c-32)(I-865) to (I-891) (I-a-1) to (I-a-27) (I-c-33) (I-892) to (I-918)(I-a-1) to (I-a-27) (I-c-34) (I-919) to (I-945) (I-a-1) to (I-a-27)(I-c-35) (I-946) to (I-972) (I-a-1) to (I-a-27) (I-c-36) (I-973) to(I-999) (I-a-1) to (I-a-27) (I-c-37) (I-1000) to (I-1026) (I-a-1) to(I-a-27) (I-c-38) (I-1027) to (I-1053) (I-a-1) to (I-a-27) (I-c-39)(I-1054) to (I-1080) (I-a-1) to (I-a-27) (I-c-40) (I-1081) to (I-1107)(I-a-1) to (I-a-27) (I-c-41) (I-1108) to (I-1134) (I-a-1) to (I-a-27)(I-c-42) (I-1135) to (I-1161) (I-a-1) to (I-a-27) (I-c-43) (I-1162) to(I-1188) (I-a-1) to (I-a-27) (I-c-44) (I-1189)~(I-1215) (I-a-1)~(I-a-27)(I-c-45) (I-1216)~(I-1242) (I-a-1)~(I-a-27) (I-c-46) (I-1243)~(I-1269)(I-a-1)~(I-a-27) (I-c-47) (I-1270)~(I-1296) (I-a-1)~(I-a-27) (I-c-48)(I-1297)~(I-1323) (I-a-1)~(I-a-27) (I-c-49) (I-1324)~(I-1350)(I-a-1)~(I-a-27) (I-c-50) (I-1351)~(I-1377) (I-a-1)~(I-a-27) (I-c-51)(I-1378)~(I-1404) (I-a-1)~(I-a-27) (I-c-52) (I-1405)~(I-1431)(I-a-1)~(I-a-27) (I-c-53) (I-1432)~(I-1458) (I-a-1)~(I-a-27) (I-c-54)(I-1459)~(I-1485) (I-a-1)~(I-a-27) (I-c-55) (I-1486)~(I-1512)(I-a-1)~(I-a-27) (I-c-56) (I-1513)~(I-1539) (I-a-1)~(I-a-27) (I-c-57)(I-1540)~(I-1566) (I-a-1)~(I-a-27) (I-c-58) (I-1567)~(I-1593)(I-a-1)~(I-a-27) (I-c-59) (I-1594)~(I-1620) (I-a-1)~(I-a-27) (I-c-60)(I-1621)~(I-1647) (I-a-1)~(I-a-27) (I-c-61) (I-1648)~(I-1674)(I-a-1)~(I-a-27) (I-c-62) (I-1675)~(I-1701) (I-a-1)~(I-a-27) (I-c-63)(I-1702)~(I-1728) (I-a-1)~(I-a-27) (I-c-64) (I-1729)~(I-1755)(I-a-1)~(I-a-27) (I-c-65) (I-1756)~(I-1782) (I-a-1)~(I-a-27) (I-c-66)(I-1783)~(I-1809) (I-a-1)~(I-a-27) (I-c-67) (I-1810)~(I-1836)(I-a-1)~(I-a-27) (I-c-68) (I-1837)~(I-1863) (I-a-1)~(I-a-27) (I-c-69)(I-1864)~(I-1890) (I-a-1)~(I-a-27) (I-c-70) (I-1891)~(I-1917)(I-a-1)~(I-a-27) (I-c-71) (I-1918)~(I-1944) (I-a-1)~(I-a-27) (I-c-72)(I-1945)~(I-1971) (I-a-1)~(I-a-27) (I-c-73) (I-1972)~(I-1998)(I-a-1)~(I-a-27) (I-c-74) (I-1999)~(I-2025) (I-a-1)~(I-a-27) (I-c-75)(I-2026)~(I-2052) (I-a-1)~(I-a-27) (I-c-76) (I-2053)~(I-2079)(I-a-1)~(I-a-27) (I-c-77) (I-2080)~(I-2106) (I-a-1)~(I-a-27) (I-c-78)(I-2107)~(I-2133) (I-a-1)~(I-a-27) (I-c-79) (I-2134)~(I-2160)(I-a-1)~(I-a-27) (I-c-80) (I-2161)~(I-2187) (I-a-1)~(I-a-27) (I-c-81)(I-2188)~(I-2214) (I-a-1)~(I-a-27) (I-c-82) (I-2215)~(I-2241)(I-a-1)~(I-a-27) (I-c-83) (I-2242)~(I-2268) (I-a-1)~(I-a-27) (I-c-84)(I-2269)~(I-2295) (I-a-1)~(I-a-27) (I-c-85) (I-2296)~(I-2322)(I-a-1)~(I-a-27) (I-c-86) (I-2323)~(I-2349) (I-a-1)~(I-a-27) (I-c-87)(I-2350)~(I-2376) (I-a-1)~(I-a-27) (I-c-88) (I-2377)~(I-2403)(I-a-1)~(I-a-27) (I-c-89) (I-2404)~(I-2430) (I-a-1)~(I-a-27) (I-c-90)(I-2431)~(I-2457) (I-a-1)~(I-a-27) (I-c-91) (I-2458)~(I-2484)(I-a-1)~(I-a-27) (I-c-92) (I-2485)~(I-2511) (I-a-1)~(I-a-27) (I-c-93)(I-2512)~(I-2538) (I-a-1)~(I-a-27) (I-c-94) (I-2539)~(I-2565)(I-a-1)~(I-a-27) (I-c-95) (I-2566)~(I-2592) (I-a-1)~(I-a-27) (I-c-96)(I-2593)~(I-2619) (I-a-1)~(I-a-27) (I-c-97) (I-2620)~(I-2646)(I-a-1)~(I-a-27) (I-c-98) (I-2647)~(I-2673) (I-a-1)~(I-a-27) (I-c-99)(I-2674)~(I-2700) (I-a-1)~(I-a-27) (I-c-100) (I-2701)~(I-2727)(I-a-1)~(I-a-27) (I-c-101) (I-2728)~(I-2754) (I-a-1)~(I-a-27) (I-c-102)(I-2755)~(I-2781) (I-a-1)~(I-a-27) (I-c-103) (I-2782)~(I-2808)(I-a-1)~(I-a-27) (I-c-104) (I-2809)~(I-2835) (I-a-1)~(I-a-27) (I-c-105)(I-2836)~(I-2862) (I-a-1)~(I-a-27) (I-c-106) (I-2863)~(I-2889)(I-a-1)~(I-a-27) (I-c-107) (I-2890)~(I-2916) (I-a-1)~(I-a-27) (I-c-108)

Of these, the carboxylate (I) is preferably carboxylate (I-1) tocarboxylate (I-12), carboxylate (I-28) to carboxylate (I-39),carboxylate (I-55) to carboxylate (I-66), carboxylate (I-82) tocarboxylate (I-93), carboxylate (I-109) to carboxylate (I-120),carboxylate (I-136) to carboxylate (I-147), carboxylate (I-163) tocarboxylate (I-174), carboxylate (I-190) to carboxylate (I-201),carboxylate (I-217) to carboxylate (I-228), carboxylate (I-244) tocarboxylate (I-255), carboxylate (I-271) to carboxylate (I-282),carboxylate (I-298) to carboxylate (I-309), carboxylate (I-325) tocarboxylate (I-336), carboxylate (I-352) to carboxylate (I-363),carboxylate (I-379) to carboxylate (I-390), carboxylate (I-406) tocarboxylate (I-417), carboxylate (I-433) to carboxylate (I-444),carboxylate (I-460) to carboxylate (I-471), carboxylate (I-487) tocarboxylate (I-498), carboxylate (I-514) to carboxylate (I-525),carboxylate (I-541) to carboxylate (I-552), carboxylate (I-568) tocarboxylate (I-579), carboxylate (I-595) to carboxylate (I-606),carboxylate (I-622) to carboxylate (I-633), carboxylate (I-649) tocarboxylate (I-660), carboxylate (I-676) to carboxylate (I-687),carboxylate (I-703) to carboxylate (I-714), carboxylate (I-730) tocarboxylate (I-741), carboxylate (I-757) to carboxylate (I-768),carboxylate (I-784) to carboxylate (I-795), carboxylate (I-811) tocarboxylate (I-822), carboxylate (I-838) to carboxylate (I-849),carboxylate (I-865) to carboxylate (I-876), carboxylate (I-892) tocarboxylate (I-903), carboxylate (I-919) to carboxylate (I-930),carboxylate (I-946) to carboxylate (I-957), carboxylate (I-973) tocarboxylate (I-984), carboxylate (I-1000) to carboxylate (I-1011),carboxylate (I-1027) to carboxylate (I-1038), carboxylate (I-1054) tocarboxylate (I-1065), carboxylate (I-1081) to carboxylate (I-1092),carboxylate (I-1108) to carboxylate (I-1119), carboxylate (I-1135) tocarboxylate (I-1146) and carboxylate (I-1162) to carboxylate (I-1173),carboxylate (I-1189) to carboxylate (I-1200), carboxylate (I-1216) tocarboxylate (I-1227), carboxylate (I-1243) to carboxylate (I-1254),carboxylate (I-1270) to carboxylate (I-1281), carboxylate (I-1297) tocarboxylate (I-1308), carboxylate (I-1324) to carboxylate (I-1335),carboxylate (I-1351) to carboxylate (I-1362), carboxylate (I-1378) tocarboxylate (I-1389), carboxylate (I-1405) to carboxylate (I-1416),carboxylate (I-1432) to carboxylate (I-1443), carboxylate (I-1459) tocarboxylate (I-1470), carboxylate (I-1486) to carboxylate (I-1497),carboxylate (I-1513) to carboxylate (I-1524), carboxylate (I-1540) tocarboxylate (I-1551), carboxylate (I-1567) to carboxylate (I-1578),carboxylate (I-1594) to carboxylate (I-1605), carboxylate (I-1621) tocarboxylate (I-1632), carboxylate (I-1648) to carboxylate (I-1659),carboxylate (I-1675) to carboxylate (I-1686), carboxylate (I-1702) tocarboxylate (I-1713), carboxylate (I-1729) to carboxylate (I-1740),carboxylate (I-1756) to carboxylate (I-1767), carboxylate (I-1783) tocarboxylate (I-1794), carboxylate (I-1810) to carboxylate (I-1821),carboxylate (I-1837) to carboxylate (I-1848), carboxylate (I-1864) tocarboxylate (I-1875), carboxylate (I-1891) to carboxylate (I-1902),carboxylate (I-1918) to carboxylate (I-1929), carboxylate (I-1945) tocarboxylate (I-1956), carboxylate (I-1972) to carboxylate (I-1983),carboxylate (I-1999) to carboxylate (I-2010), carboxylate (I-2026) tocarboxylate (I-2037), carboxylate (I-2053) to carboxylate (I-2064),carboxylate (I-2080) to carboxylate (I-2091), carboxylate (I-2107) tocarboxylate (I-2118), carboxylate (I-2134) to carboxylate (I-2145),carboxylate (I-2161) to carboxylate (I-2172), carboxylate (I-2188) tocarboxylate (I-2199), carboxylate (I-2215) to carboxylate (I-2226),carboxylate (I-2242) to carboxylate (I-2253), carboxylate (I-2269) tocarboxylate (I-2280), carboxylate (I-2296) to carboxylate (I-2307),carboxylate (I-2323) to carboxylate (I-2334), carboxylate (I-2350) tocarboxylate (I-2361), carboxylate (I-2377) to carboxylate (I-2388),carboxylate (I-2404) to carboxylate (I-2415), carboxylate (I-2431) tocarboxylate (I-2442), carboxylate (I-2458) to carboxylate (I-2469),carboxylate (I-2485) to carboxylate (I-2496), carboxylate (I-2512) tocarboxylate (I-2523), carboxylate (I-2539) to carboxylate (I-2550),carboxylate (I-2566) to carboxylate (I-2577), carboxylate (I-2593) tocarboxylate (I-2604), carboxylate (I-2620) to carboxylate (I-2631),carboxylate (I-2647) to carboxylate (I-2658), carboxylate (I-2674) tocarboxylate (I-2685), carboxylate (I-2701) to carboxylate (I-2712),carboxylate (I-2728) to carboxylate (I-2739), carboxylate (I-2755) tocarboxylate (I-2766), carboxylate (I-2782) to carboxylate (I-2793),carboxylate (I-2809) to carboxylate (I-2820), carboxylate (I-2836) tocarboxylate (I-2847), carboxylate (I-2863) to carboxylate (I-2874),carboxylate (I-2890) to carboxylate (I-2901).

<Method for Producing Carboxylate (I)>

The carboxylate (I) can be produced by reacting a salt represented byformula (I-a) with a salt represented by formula (I-b) in a solvent:

wherein symbols R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R^(bb1), m1, m2, m3, m4, m5, m6,m7, m8, m9, A¹, A², A³, X⁰, X¹⁰ and L¹⁰ are the same as defined above.

Examples of the solvent in this reaction include chloroform,acetonitrile, ion-exchanged water and the like.

The reaction temperature is usually 15° C. to 80° C., and the reactiontime is usually 0.5 to 24 hours.

Examples of the salt represented by formula (I-a) include saltsrepresented by the following formulas. These salts can be easilyproduced by the method mentioned in JP 2020-15713 A, or a knownproduction method.

The salt represented by formula (I-b) can be produced by reacting acompound represented by formula (I-c) with silver oxide in a solvent.

wherein all symbols are the same as defined above.

Examples of the solvent in this reaction include chloroform,acetonitrile and the like.

The reaction temperature is usually 15° C. to 80° C., and the reactiontime is usually 0.5 to 24 hours.

Examples of the compound represented by formula (I-c) include compoundsrepresented by the following formulas and the like. These compound areeasily available on the market, or can be easily produced by a knownproduction method.

[Carboxylic Acid Generator]

The carboxylic acid generator of the present disclosure is an acidgenerator including a carboxylate (I). The carboxylate (I) of thepresent disclosure can act as an acid generator in the resistcomposition. When using the carboxylate (I) as the acid generator in theresist composition, the acid generator may include the carboxylate (I)alone, or two or more thereof.

As mentioned later, the acid generator of the present disclosure mayfurther include an acid generator known in the resist field other thanthe carboxylate (I) (hereinafter sometimes referred to as “acidgenerator (B)”) and/or a carboxylic acid generator known in the resistfield other than the carboxylate (I). The acid generator (B) may be usedalone, or in combination of two or more thereof.

When the carboxylic acid generator of the present disclosure includesthe acid generator (B), a ratio of the content of the carboxylate (I) tothat of the acid generator (B) (mass ratio; carboxylate (I):acidgenerator (B)) is usually 1:99 to 100:0, preferably 1:99 to 99:1, morepreferably 2:98 to 98:2, and still more preferably 5:95 to 95:5.

[Structural Unit Derived from Salt Represented by Formula (I)]

The structural unit derived from a salt represented by formula (I) is astructural unit represented by formula (IP) (hereinafter sometimesreferred to as “structural unit (IP)”).

Such structural unit (IP) also functions as the acid generator similarlyto the salt (I), and also functions as the structural unit constitutingthe compound or the resin.

[Structural Unit Derived from Carboxylate Represented by Formula (I)]

The resin of the present disclosure is a resin including a structuralunit (IP) derived from a carboxylate represented by formula (I)(hereinafter sometimes referred to as “resin (Ap)”).

wherein symbols R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R^(bb1), m1, m2, m3, m4, m5, m6,m7, m8, m9, A¹, A², A³, X⁰, X¹⁰ and L¹⁰ are respectively the same asdefined above.

The structural unit (IP) indicates a state where a double bondCH₂═C—R^(bb1) included in the salt (I) is cleaved.

The resin (Ap) may be either a homopolymer including the structural unit(IP) alone, or a copolymer including two or more structural units (IP).

The resin (Ap) may include a structural unit other than the structuralunit (IP). As mentioned later, examples of the structural unit otherthan the structural unit (IP) include a structural unit having anacid-labile group (hereinafter sometimes referred to as “structural unit(a1)”), a structural unit having no acid-labile group (hereinaftersometimes referred to as “structural unit (s)”), other structural unit(hereinafter sometimes referred to as “structural unit (t)”) and astructural unit known in the relevant field. Here, the “acid-labilegroup” means a group having a leaving group which is eliminated bycontact with an acid, thus converting a constitutional unit into aconstitutional unit having a hydrophilic group (e.g. a hydroxy group ora carboxy group).

The content of the structural unit (IP) is usually 0.1 to 100 mol %,preferably 0.5 to 50 mol %, more preferably 0.8 to 30 mol %, and stillmore preferably 1 to 10 mol %, based on the total amount of the resin(Ap).

As mentioned later, when the resin (Ap) is used for a resistcomposition, it may preferably include, in addition to the structuralunit (IP), a structural unit (a1).

As mentioned later, when the resin (Ap) is used for a resistcomposition, regardless of whether or not the structural unit (a1) isincluded, it may be used in combination with a resin including astructural unit (a1) (hereinafter sometimes referred to as “resin (A)”)and/or a resin other than the resin (A). Hereinafter, the resin (Ap)and/or the resin (A) is/are sometimes referred to as “resin (A) and/orthe like”.

It is preferable that the resin (Ap) and the resin (A) further include astructural unit other than the structural unit (a1).

Examples of the structural unit other than the structural unit (a1)include a structural unit having no acid-labile group (hereinaftersometimes referred to as “structural unit (s)”), other structural unit(hereinafter sometimes referred to as “structural unit (t)”) and astructural unit known in the relevant field.

<Structural Unit (a1)>

The structural unit (a1) is derived from a monomer having an acid-labilegroup (hereinafter sometimes referred to as “monomer (a1)”).

The acid-labile group contained in the resin (A) is preferably a grouprepresented by formula (1) (hereinafter also referred to as group (1))and/or a group represented by formula (2) (hereinafter also referred toas group (2)):

wherein, in formula (1), R^(a1), R^(a2) and R^(a3) each independentlyrepresent an alkyl group having 1 to 8 carbon atoms, an alkenyl grouphaving 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to20 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbonatoms, or a group obtained by combining these groups, and R^(a1) andR^(a2) are bonded to each other to form a nonaromatic hydrocarbon ringhaving 3 to 20 carbon atoms together with carbon atoms to which R^(a1)and R^(a2) are bonded,

ma and na each independently represent 0 or 1, and at least one of maand na represents 1, and

* represents a bonding site:

wherein, in formula (2), R^(a1′) and R^(a2′) each independentlyrepresent a hydrogen atom or a hydrocarbon group having 1 to 12 carbonatoms, R^(a3′) represents a hydrocarbon group having 1 to 20 carbonatoms, or R^(a2′) and R^(a3′) are bonded to each other to form aheterocyclic ring having 3 to 20 carbon atoms together with carbon atomsand X to which R^(a2′) and R^(a3′) are bonded, and —CH₂— included in thehydrocarbon group and the heterocyclic ring may be replaced by —O— or—S—,

X represents an oxygen atom or a sulfur atom,

na′ represents 0 or 1, and

* represents a bonding site.

Examples of the alkyl group in R^(a1), R^(a2) and R^(a3) include amethyl group, an ethyl group, a propyl group, a butyl group, a pentylgroup, a hexyl group, a heptyl group, an octyl group and the like.

Examples of the alkenyl group in R^(a1), R^(a2) and R^(a3) include anethenyl group, a propenyl group, an isopropenyl group, a butenyl group,an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenylgroup, a heptenyl group, an octenyl group, an isooctenyl group and anonenyl group.

The alicyclic hydrocarbon group in R^(a1), R^(a2) and R^(a3) may beeither monocyclic or polycyclic. Examples of the monocyclic alicyclichydrocarbon group include cycloalkyl groups such as a cyclopentyl group,a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Examplesof the polycyclic alicyclic hydrocarbon group include adecahydronaphthyl group, an adamantyl group, a norbornyl group and thefollowing groups (* represents a bonding site). The number of carbonatoms of the alicyclic hydrocarbon group of R^(a1), R^(a2) and R^(a3) ispreferably 3 to 16.

Examples of the aromatic hydrocarbon group in R^(a1), R^(a2) and R^(a3)include aryl groups such as a phenyl group, a naphthyl group, an anthrylgroup, a biphenyl group and a phenanthryl group.

Examples of the combined group include groups obtained by combining theabove-mentioned alkyl group and alicyclic hydrocarbon group (e.g.,alkylcycloalkyl groups or cycloalkylalkyl groups, such as amethylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornylgroup, a cyclohexylmethyl group, an adamantylmethyl group, anadamantyldimethyl group and a norbornylethyl group), aralkyl groups suchas a benzyl group, aromatic hydrocarbon groups having an alkyl group (ap-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylylgroup, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups havingan alicyclic hydrocarbon group (a p-cyclohexylphenyl group, ap-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as aphenylcyclohexyl group, and the like.

Preferably, ma is 0 and na is 1.

When R^(a1) and R^(a2) are bonded to each other to form a nonaromatichydrocarbon ring, examples of —C(R^(a1)) (R^(a2)) (R^(a3)) include thefollowing rings. The nonaromatic hydrocarbon ring preferably has 3 to 12carbon atoms. * represents a bonding site to —O—.

Examples of the hydrocarbon group in R^(a1′), R^(a2′) and R^(a3′)include an alkyl group, an alicyclic hydrocarbon group, an aromatichydrocarbon group, and groups formed by combining these groups.

Examples of the alkyl group and the alicyclic hydrocarbon group includethose which are the same as mentioned in R^(a1), R^(a2) and R^(a3).

Examples of the aromatic hydrocarbon group include aryl groups such as aphenyl group, a naphthyl group, an anthryl group, a biphenyl group and aphenanthryl group.

Examples of the combined group include groups obtained by combining theabove-mentioned alkyl group and alicyclic hydrocarbon group (e.g.,alkylcycloalkyl groups or cycloalkylalkyl groups, such as amethylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornylgroup, a cyclohexylmethyl group, an adamantylmethyl group, anadamantyldimethyl group and a norbornylethyl group), aralkyl groups suchas a benzyl group, aromatic hydrocarbon groups having an alkyl group (ap-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylylgroup, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups havingan alicyclic hydrocarbon group (a p-cyclohexylphenyl group, ap-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as aphenylcyclohexyl group and the like.

When R^(a2′) and R^(a3′) are bonded to each other to form a heterocyclicring together with carbon atoms and X to which R^(a2′) and R^(a3′) arebonded, examples of —C(R^(a1′)) (R^(a2′))—X—R^(a3′) include thefollowing rings. * represents a bonding site.

At least one of R^(a1′) and R^(a2′) is preferably a hydrogen atom.

na′ is preferably 0.

Examples of the group (1) include the following groups.

A group wherein, in formula (1), R^(a1), R^(a2) and R^(a3) are alkylgroups, ma=0 and na=1. The group is preferably a tert-butoxycarbonylgroup.

A group wherein, in formula (1), R^(a1) and R^(a2) are bonded to eachother to form an adamantyl group together with carbon atoms to whichR^(a1) and R^(a2) are bonded, R^(a3) is an alkyl group, ma=0 and na=1.

A group wherein, in formula (1), R^(a1) and R^(a2) are eachindependently an alkyl group, R^(a3) is an adamantyl group, ma=0 andna=1.

Specific examples of the group (1) include the following groups. *represents a bonding site.

Specific examples of the group (2) include the following groups. *represents a bonding site.

The monomer (a1) is preferably a monomer having an acid-labile group andan ethylenic unsaturated bond, and more preferably a (meth)acrylicmonomer having an acid-labile group.

Of the (meth)acrylic monomers having an acid-labile group, those havingan alicyclic hydrocarbon group having 5 to 20 carbon atoms arepreferably exemplified. When a resin (A) including a structural unitderived from a monomer (a1) having a bulky structure such as analicyclic hydrocarbon group is used in a resist composition, it ispossible to improve the resolution of a resist pattern.

The structural unit derived from a (meth)acrylic monomer having a group(1) includes a structural unit represented by formula (a1-0)(hereinafter sometimes referred to as structural unit (a1-0)), astructural unit represented by formula (a1-1) (hereinafter sometimesreferred to as structural unit (a1-1)) or a structural unit representedby formula (a1-2) (hereinafter sometimes referred to as structural unit(a1-2)). Preferably, the structural unit is at least one structural unitselected from the group consisting of structural unit (a1-0), structuralunit (a1-1) and structural unit (a1-2), and more preferably at least onestructural unit selected from the group consisting of structural unit(a1-1) and structural unit (a1-2). These structural units may be usedalone, or two or more structural units may be used in combination.

In formula (a1-0), formula (a1-1) and formula (a1-2),

L^(a01), L^(a1) and L^(a2) each independently represent —O— or*—O—(CH₂)_(k1)—CO—O—, k1 represents an integer of 1 to 7, and *represents a bonding site to —CO—,

R^(a01), R^(a4) and R^(a5) each independently represent a hydrogen atom,a halogen atom or an alkyl group having 1 to 6 carbon atoms which mayhave a halogen atom,

R^(a02), R^(a03) and R^(a04) each independently represent an alkyl grouphaving 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbonatoms, or a group obtained by combining these groups,

R^(a6) and R^(a7) each independently represent an alkyl group having 1to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, analicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatichydrocarbon group having 6 to 18 carbon atoms, or a group obtained bycombining these groups,

m1 represents an integer of 0 to 14,

n1 represents an integer of 0 to 10, and

n1′ represents an integer of 0 to 3.

R^(a01), R^(a4) and R^(a5) are preferably a hydrogen atom or a methylgroup, and more preferably a methyl group.

L^(a01), L^(a1) and L^(a2) are preferably an oxygen atom or*—O—(CH₂)_(k01)—CO—O— (in which k01 is preferably an integer of 1 to 4,and more preferably 1), and more preferably an oxygen atom.

Examples of the alkyl group, the alicyclic hydrocarbon group, thearomatic hydrocarbon group, and groups obtained by combining thesegroups in R^(a02), R^(a03) and R^(a04) include the same groups asmentioned as for R^(a1), R^(a2) and R^(a3) of the group (1).

Examples of the alkyl group, the alkenyl group, the alicyclichydrocarbon group, the aromatic hydrocarbon group, and groups obtainedby combining these groups in R^(a6) and R^(a7) include the same groupsas mentioned as for R^(a1), R^(a2) and R^(a3) of formula (1).

The alkyl group in R^(a02), R^(a03) and R^(a04) is preferably an alkylgroup having 1 to 6 carbon atoms, more preferably a methyl group or anethyl group, and still more preferably a methyl group.

The alkyl group in R^(a6) and R^(a7) is preferably an alkyl group having1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, anisopropyl group or a t-butyl group, and still more preferably an ethylgroup, an isopropyl group or a t-butyl group.

The alkenyl group in R^(a6) and R^(a7) is preferably an alkenyl grouphaving 2 to 6 carbon atoms, and more preferably an ethenyl group, apropenyl group, an isopropenyl group or a butenyl group.

The number of carbon atoms of the alicyclic hydrocarbon group as forR^(a02), R^(a03), R^(a04), R^(a6) and R^(a7) is preferably 5 to 12, andmore preferably 5 to 10.

The number of carbon atoms of the aromatic hydrocarbon group of R^(a02),R^(a03), R^(a04), R^(a6) and R^(a7) is preferably 6 to 12, and morepreferably 6 to 10.

The total number of carbon atoms of the group obtained by combining thealkyl group with the alicyclic hydrocarbon group is preferably 18 orless.

The total number of carbon atoms of the group obtained by combining thealkyl group with the aromatic hydrocarbon group is preferably 18 orless.

R^(a02) and R^(a03) are preferably an alkyl group having 1 to 6 carbonatoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, andmore preferably a methyl group, an ethyl group, a phenyl group or anaphthyl group.

R^(a04) is preferably an alkyl group having 1 to 6 carbon atoms or analicyclic hydrocarbon group having 5 to 12 carbon atoms, and morepreferably a methyl group, an ethyl group, a cyclohexyl group or anadamantyl group.

Preferably, R^(a6) and R^(a7) are each independently an alkyl grouphaving 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atomsor an aromatic hydrocarbon group having 6 to 12 carbon atoms, morepreferably a methyl group, an ethyl group, an isopropyl group, a t-butylgroup, an ethenyl group, a phenyl group or a naphthyl group, and stillmore preferably an ethyl group, an isopropyl group, a t-butyl group, anethenyl group or a phenyl group.

m1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

n1′ is preferably 0 or 1.

The structural unit (a1-0) includes, for example, a structural unitrepresented by any one of formula (a1-0-1) to formula (a1-0-18) and astructural unit in which a methyl group corresponding to R^(a01) in thestructural unit (a1-0) is substituted with a hydrogen atom, a halogenatom, a haloalkyl group or other alkyl groups, and is preferably astructural unit represented by any one of formula (a1-0-1) to formula(a1-0-10), formula (a1-0-13) and formula (a1-0-14).

The structural unit (a1-1) includes, for example, structural unitsderived from the monomers mentioned in JP 2010-204646 A. Of thesestructural units, a structural unit represented by any one of formula(a1-1-1) to formula (a1-1-7) and a structural unit in which a methylgroup corresponding to R^(a4) in the structural unit (a1-1) issubstituted with a hydrogen atom, a halogen atom, a haloalkyl group orother alkyl groups are preferable, and a structural unit represented byany one of formula (a1-1-1) to formula (a1-1-4) is more preferable.

Examples of the structural unit (a1-2) include a structural unitrepresented by any one of formula (a1-2-1) to formula (a1-2-14), and astructural unit in which a methyl group corresponding to R^(a5) in thestructural unit (a1-2) is substituted with a hydrogen atom, a halogenatom, a haloalkyl group or other alkyl groups, and a structure unitrepresented by any one of formula (a1-2-2), formula (a1-2-5), formula(a1-2-6) and formula (a1-2-10) to formula (a1-2-14) is preferable.

When the resin (A) or the like contains the structural unit (a1-0)and/or the structural unit (a1-1) and/or the structural unit (a1-2), thetotal content of these is the resin (A) or the like. 10 mol % or more,preferably 15 mol % or more, more preferably 20 mol % or more, stillmore preferably 25 mol % or more, still more preferably 30 mol %, basedon the total structural units % or more. Further, it is 95 mol % orless, preferably 90 mol % or less, more preferably 85 mol % or less,still more preferably 70 mol % or less. Specifically, it is 10 to 95 mol%, preferably 15 to 90 mol %, more preferably 20 to 85 mol %, still morepreferably 25 to 70 mol %, still more preferably 30 to 70 mol %.

When the resin (A) or the like contains the structural unit (a1-0), thecontent thereof may be 5 mol % or more, preferably 10 mol % or more,based on the total structural units of the resin (A). be. Also, it is 80mol % or less, preferably 75 mol % or less, and more preferably 70 mol %or less. Specifically, it is usually 5 to 80 mol, preferably 5 to 75mol, more preferably 10 to 70 mol %.

When the resin (A) or the like contains the structural unit (a1-1)and/or the structural unit (a1-2), the total content of these is usually10 mol with respect to the total structural units of the resin (A) orthe like. % or more, preferably 15 mol % or more, more preferably 20 mol% or more. Also, it is 90 mol % or less, preferably 85 mol % or less,more preferably 80 mol % or less, still more preferably 75 mol % orless, and even more preferably 70 mol % or less. Specifically, it is 10to 90 mol %, preferably 15 to 85 mol %, more preferably 20 to 80 mol %,still more preferably 20 to 75 mol %, still more preferably 20˜70 mol %.

In the structural unit (a1), examples of the structural unit having agroup (2) include a structural unit represented by formula (a1-4)(hereinafter sometimes referred to as “structural unit (a1-4)”):

wherein, in formula (a1-4),

R^(a32) represents a hydrogen atom, a halogen atom, or an alkyl grouphaving 1 to 6 carbon atoms which may have a halogen atom,

R^(a33) represents a halogen atom, a hydroxy group, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy grouphaving 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbonatoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, anacryloyloxy group or a methacryloyloxy group,

A^(a30) represents a single bond or *—X^(a31)-(A^(a32)-X^(a32)) and *represents a bonding site to carbon atoms to which —R^(a32) is bonded,

A^(a32) represents an alkanediyl group having 1 to 6 carbon atoms,

X^(a31) and X^(a32) each independently represent —O—, —CO—O— or —O—CO—,

nc represents 0 or 1,

la represents an integer of 0 to 4, and when la is an integer of 2 ormore, a plurality of R^(a33) may be the same or different from eachother, and

R^(a34) and R^(a35) each independently represent a hydrogen atom or ahydrocarbon group having 1 to 12 carbon atoms, R^(a36) represents ahydrocarbon group having 1 to 20 carbon atoms, or R^(a35) and R^(a36)are bonded to each other to form a divalent hydrocarbon group having 2to 20 carbon atoms together with —C—O— to which R^(a35) and R^(a36) arebonded, and —CH₂— included in the hydrocarbon group and the divalenthydrocarbon group may be replaced by —O— or —S—.

Examples of the halogen atom in R^(a32) and R^(a33) include a fluorineatom, a chlorine atom and a bromine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have ahalogen atom in R^(a32) include a trifluoromethyl group, adifluoromethyl group, a methyl group, a perfluoroethyl group, a2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethylgroup, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, apropyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutylgroup, a butyl group, a perfluoropentyl group, a2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl groupand a perfluorohexyl group.

R^(a32) is preferably a hydrogen atom or an alkyl group having 1 to 4carbon atoms, more preferably a hydrogen atom, a methyl group or anethyl group, and still more preferably a hydrogen atom or a methylgroup.

Examples of the alkyl group in R^(a33) include a methyl group, an ethylgroup, a propyl group, an isopropyl group, a butyl group, a sec-butylgroup, a tert-butyl group, a pentyl group and a hexyl group. The alkylgroup is preferably an alkyl group having 1 to 4 carbon atoms, morepreferably a methyl group or an ethyl group, and still more preferably amethyl group.

Examples of the alkoxy group in R^(a33) include a methoxy group, anethoxy group, a propoxy group, an isopropoxy group, a butoxy group, asec-butoxy group, a tert-butoxy group, a pentyloxy group and a hexyloxygroup. The alkoxy group is preferably an alkoxy group having 1 to 4carbon atoms, more preferably a methoxy group or an ethoxy group, andstill more preferably a methoxy group.

Examples of the alkoxyalkyl group in R^(a33) include a methoxymethylgroup, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethylgroup, a butoxymethyl group, a sec-butoxymethyl group and atert-butoxymethyl group. The alkoxyalkyl group is preferably analkoxyalkyl group having 2 to 8 carbon atoms, more preferably amethoxymethyl group or an ethoxyethyl group, and still more preferably amethoxymethyl group.

Examples of the alkoxyalkoxy group in R^(a33) include a methoxymethoxygroup, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxygroup, a propoxymethoxy group, an isopropoxymethoxy group, abutoxymethoxy group, a sec-butoxymethoxy group and a tert-butoxymethoxygroup. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having2 to 8 carbon atoms, and more preferably a methoxyethoxy group or anethoxyethoxy group.

Examples of the alkylcarbonyl group in R^(a33) include an acetyl group,a propionyl group and a butyryl group. The alkylcarbonyl group ispreferably an alkylcarbonyl group having 2 to 3 carbon atoms, and morepreferably an acetyl group.

Examples of the alkylcarbonyloxy group in R^(a33) include an acetyloxygroup, a propionyloxy group and a butyryloxy group. The alkylcarbonyloxygroup is preferably an alkylcarbonyloxy group having 2 to 3 carbonatoms, and more preferably an acetyloxy group.

R^(a33) is preferably a halogen atom, a hydroxy group, an alkyl grouphaving 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atomsor an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably afluorine atom, an iodine atom, a hydroxy group, a methyl group, amethoxy group, an ethoxy group, an ethoxyethoxy group or anethoxymethoxy group, and still more preferably a fluorine atom, aniodine atom, a hydroxy group, a methyl group, a methoxy group or anethoxyethoxy group.

Examples of the *—X^(a31)-(A^(a32)-X^(a32))_(nc)— include *—O—, *—CO—O—,*—O—CO—, *—CO—O-A^(a32)-CO—O—, *—O—CO-A^(a32)-O—, *—O-A^(a32)-CO—O—,*—CO—O-A^(a32)-O—CO— and *—O—CO-A^(a32)-O—CO. Of these, *—CO—O—,*—CO—O-A^(a32)-CO—O— or *—O-A^(a32)-CO—O— is preferable.

Examples of the alkanediyl group include a methylene group, an ethylenegroup, a propane-1,3-diyl group, a propane-1,2-diyl group, abutane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

A^(a32) is preferably a methylene group or an ethylene group.

A^(a30) is preferably a single bond, *—CO—O— or *—CO—O-A^(a32)-CO—O—,more preferably a single bond, *—CO—O— or *—CO—O—CH₂—CO—O—, and stillmore preferably a single bond or *—CO—O—.

la is preferably 0, 1 or 2, more preferably 0 or 1, and still morepreferably 0.

Examples of the hydrocarbon group in R^(a34), R^(a35) and R^(a36)include an alkyl group, an alicyclic hydrocarbon group, an aromatichydrocarbon group, and groups obtained by combining these groups.

Examples of the alkyl group include a methyl group, an ethyl group, apropyl group, a butyl group, a pentyl group, a hexyl group, a heptylgroup, an octyl group and the like.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic.Examples of the monocyclic alicyclic hydrocarbon group includecycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, acycloheptyl group and a cyclooctyl group. Examples of the polycyclicalicyclic hydrocarbon group include a decahydronaphthyl group, anadamantyl group, a norbornyl group, and the following groups (*represents a bonding site).

Examples of the aromatic hydrocarbon group include aryl groups such as aphenyl group, a naphthyl group, an anthryl group, a biphenyl group and aphenanthryl group.

Examples of the combined group include groups obtained by combining theabove-mentioned alkyl group and alicyclic hydrocarbon group (e.g.,alkylcycloalkyl groups or cycloalkylalkyl groups, such as amethylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornylgroup, a cyclohexylmethyl group, an adamantylmethyl group, anadamantyldimethyl group and a norbornylethyl group), aralkyl groups suchas a benzyl group, aromatic hydrocarbon groups having an alkyl group (ap-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylylgroup, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups havingan alicyclic hydrocarbon group (a p-cyclohexylphenyl group, ap-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as aphenylcyclohexyl group and the like. Particularly, examples of R^(a36)include an alkyl group having 1 to 18 carbon atoms, an alicyclichydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbongroup having 6 to 18 carbon atoms, or a group formed by combining thesegroups.

R^(a34) is preferably a hydrogen atom.

R^(a35) is preferably a hydrogen atom, an alkyl group having 1 to 12carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbonatoms, and more preferably a methyl group or an ethyl group.

The hydrocarbon group of R^(a36) is preferably an alkyl group having 1to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbonatoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or agroup formed by combining these groups, and more preferably an alkylgroup having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms.The alkyl group and the alicyclic hydrocarbon group in R^(a36) arepreferably unsubstituted. The aromatic hydrocarbon group in R^(a36) ispreferably an aromatic ring having an aryloxy group having 6 to 10carbon atoms.

—OC(R^(a34)) (R^(a35))—O—R^(a36) in the structural unit (a1-4) iseliminated by contacting with an acid (e.g., p-toluenesulfonic acid) toform a hydroxy group.

—OC(R^(a34)) (R^(a35))—O—R^(a36) is preferably bonded at the m-positionor the p-position of the benzene ring.

The structural unit (a1-4) includes, for example, structural unitsderived from the monomers mentioned in JP 2010-204646 A. The structuralunit preferably includes structural units represented by formula(a1-4-1) to formula (a1-4-24) and a structural unit in which a hydrogenatom corresponding to R^(a32) in the structural unit (a1-4) issubstituted with a halogen atom, a haloalkyl group or an alkyl group,and more preferably structural units represented by formula (a1-4-1) toformula (a1-4-5), formula (a1-4-10), formula (a1-4-13), formula(a1-4-14), formula (a1-4-19) and formula (a1-4-20).

When the resin (A) includes the structural unit (a1-4), the content ispreferably 3 to 80 mol %, more preferably 5 to 75 mol %, still morepreferably 7 to 70 mol %, yet more preferably 7 to 65 mol %, andparticularly preferably 10 to 60 mol %, based on the total of allstructural units of the resin (A).

The structural unit derived from a (meth)acrylic monomer having a group(2) also includes a structural unit represented by formula (a1-5)(hereinafter sometimes referred to as “structural unit (a1-5)”).

In formula (a1-5),

R^(a8) represents an alkyl group having 1 to 6 carbon atoms which mayhave a halogen atom, a hydrogen atom or a halogen atom,

Z^(a1) represents a single bond or *—(CH₂)_(h3)—CO-L⁵⁴-, h3 representsan integer of 1 to 4, and * represents a bonding site to L⁵¹,

L⁵¹, L⁵², L⁵³ and L⁵⁴ each independently represent —O— or —S—,

s1 represents an integer of 1 to 3, and

s1′ represents an integer of 0 to 3.

The halogen atom includes a fluorine atom and a chlorine atom and ispreferably a fluorine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have ahalogen atom include a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group, a hexyl group, a heptyl group, an octylgroup, a fluoromethyl group and a trifluoromethyl group.

In formula (a1-5), R^(a8) is preferably a hydrogen atom, a methyl groupor a trifluoromethyl group,

L⁵¹ is preferably an oxygen atom, one of L⁵² and L⁵³ is preferably —O—and the other one is preferably —S—,

s1 is preferably 1,

s1′ is preferably an integer of 0 to 2, and

Z^(a1) is preferably a single bond or *—CH₂—CO—O—.

The structural unit (a1-5) includes, for example, structural unitsderived from the monomers mentioned in JP 2010-61117 A. Of thesestructural units, structural units represented by formula (a1-5-1) toformula (a1-5-4) are preferable, and structural units represented byformula (a1-5-1) or formula (a1-5-2) are more preferable.

When the resin (A) includes the structural unit (a1-5), the content ispreferably 1 to 50 mol %, more preferably 3 to 45 mol %, still morepreferably 5 to 40 mol %, and yet more preferably 5 to 30 mol %, basedon all structural units of the resin (A).

The structural unit (a1) also includes the following structural units.

When the resin (A) includes the above-mentioned structural units such as(a1-3-1) to (a1-3-7), the content is preferably 10 to 95 mol %, morepreferably 15 to 90 mol %, still more preferably 20 to 85 mol %, yetmore preferably 20 to 70 mol %, and particularly preferably 20 to 60 mol%, based on all structural units of the resin (A).

The structural unit (a1) also includes the following structural units.

When the resin (A) includes the above-mentioned structural units such as(a1-6-1) to (a1-6-3), the content is preferably 10 to 60 mol %, morepreferably 15 to 55 mol %, still more preferably 20 to 50 mol %, yetmore preferably 20 to 45 mol %, and particularly preferably 20 to 40 mol%, based on all structural units of the resin (A).

<Structural Unit (s)>

The structural unit (s) is derived from a monomer having no acid-labilegroup (hereinafter sometimes referred to as “monomer (s)”). It ispossible to use, as the monomer from which the structural unit (s) isderived, a monomer having no acid-labile group known in the resistfield.

The structural unit (s) preferably has a hydroxy group or a lactonering. When a resin including a structural unit having a hydroxy groupand having no acid-labile group (hereinafter sometimes referred to as“structural unit (a2)”) and/or a structural unit having a lactone ringand having no acid-labile group (hereinafter sometimes referred to as“structural unit (a3)”) is used in the resist composition of the presentdisclosure, it is possible to improve the resolution of a resist patternand the adhesion to a substrate.

<Structural Unit (a2)>

The hydroxy group possessed by the structural unit (a2) may be either analcoholic hydroxy group or a phenolic hydroxy group.

When a resist pattern is produced from the resist composition of thepresent disclosure, in the case of using, as an exposure source, highenergy rays such as KrF excimer laser (248 nm), electron beam or extremeultraviolet light (EUV), a structural unit (a2) having a phenolichydroxy group is preferably used as the structural unit (a2), and thebelow-mentioned structural unit (a2-A) is more preferably used. Whenusing ArF excimer laser (193 nm) or the like, a structural unit (a2)having an alcoholic hydroxy group is preferably used as the structuralunit (a2), and more preferably a structural unit (a2-1) mentioned later.The structural unit (a2) may be included alone, or two or morestructural units may be included.

In the structural unit (a2), examples of the structural unit having aphenolic hydroxy group include a structural unit represented by formula(a2-A) (hereinafter sometimes referred to as “structural unit (a2-A)”):

wherein, in formula (a2-A),

R^(a50) represents a hydrogen atom, a halogen atom, or an alkyl grouphaving 1 to 6 carbon atoms which may have a halogen atom,

R^(a51) represents a halogen atom, a hydroxy group, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy grouphaving 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbonatoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, anacryloyloxy group or a methacryloyloxy group,

A^(a50) represents a single bond or *—X^(a51)-(A^(a52)-X^(a52))_(nb)—,and * represents a bonding site to carbon atoms to which —R^(a50) isbonded,

A^(a52) represents an alkanediyl group having 1 to 6 carbon atoms,

X^(a51) and X^(a52) each independently represent —O—, —CO—O— or —O—CO—,

nb represents 0 or 1, and

mb represents an integer of 0 to 4, and when mb is an integer of 2 ormore, a plurality of R^(a51) may be the same or different from eachother.

Examples of the halogen atom in R^(a50) and R^(a51) include a fluorineatom, a chlorine atom and a bromine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have ahalogen atom in R^(a50) include a trifluoromethyl group, adifluoromethyl group, a methyl group, a perfluoroethyl group, a2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethylgroup, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, apropyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutylgroup, a butyl group, a perfluoropentyl group, a2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl groupand a perfluorohexyl group.

R^(a50) is preferably a hydrogen atom or an alkyl group having 1 to 4carbon atoms, more preferably a hydrogen atom, a methyl group or anethyl group, and still more preferably a hydrogen atom or a methylgroup.

Examples of the alkyl group in R^(a51) include a methyl group, an ethylgroup, a propyl group, an isopropyl group, a butyl group, a sec-butylgroup, a tert-butyl group, a pentyl group and a hexyl group. The alkylgroup is preferably an alkyl group having 1 to 4 carbon atoms, morepreferably a methyl group or an ethyl group, and still more preferably amethyl group.

Examples of the alkoxy group in R^(a51) include a methoxy group, anethoxy group, a propoxy group, an isopropoxy group, a butoxy group, asec-butoxy group and a tert-butoxy group. The alkoxy group is preferablyan alkoxy group having 1 to 4 carbon atoms, more preferably a methoxygroup or an ethoxy group, and still more preferably a methoxy group.

Examples of the alkoxyalkyl group in R^(a51) include a methoxymethylgroup, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethylgroup, a butoxymethyl group, a sec-butoxymethyl group and atert-butoxymethyl group. The alkoxyalkyl group is preferably analkoxyalkyl group having 2 to 8 carbon atoms, more preferably amethoxymethyl group or an ethoxyethyl group, and still more preferably amethoxymethyl group.

Examples of the alkoxyalkoxy group in R^(a51) include a methoxymethoxygroup, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxygroup, a propoxymethoxy group, an isopropoxymethoxy group, abutoxymethoxy group, a sec-butoxymethoxy group and a tert-butoxymethoxygroup. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having2 to 8 carbon atoms, and more preferably a methoxyethoxy group or anethoxyethoxy group.

Examples of the alkylcarbonyl group in R^(a51) include an acetyl group,a propionyl group and a butyryl group. The alkylcarbonyl group ispreferably an alkylcarbonyl group having 2 to 3 carbon atoms, and morepreferably an acetyl group.

Examples of the alkylcarbonyloxy group in R^(a51) include an acetyloxygroup, a propionyloxy group and a butyryloxy group. The alkylcarbonyloxygroup is preferably an alkylcarbonyloxy group having 2 to 3 carbonatoms, and more preferably an acetyloxy group.

R^(a51) is preferably a halogen atom, a hydroxy group, an alkyl grouphaving 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atomsor an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably afluorine atom, an iodine atom, a hydroxy group, a methyl group, amethoxy group, an ethoxy group, an ethoxyethoxy group or anethoxymethoxy group, and still more preferably a fluorine atom, aniodine atom, a hydroxy group, a methyl group, a methoxy group or anethoxyethoxy group.

Examples of *—X^(a51)-(A^(a52)-X^(a52))_(nb)— include *—O—, *—CO—O—,*—O—CO—, *—CO—O-A^(a52)-CO—O—, *—O—CO-A^(a52)-O—, *—O-A^(a52)-CO—O—,*—CO—O-A^(a52)-O—CO— and *—O—CO-A^(a52)-O—CO—. Of these, *—CO—O—,*—CO—O-A^(a52)-CO—O— or *—O-A^(a52)-CO—O— is preferable.

Examples of the alkanediyl group include a methylene group, an ethylenegroup, a propane-1,3-diyl group, a propane-1,2-diyl group, abutane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

A^(a52) is preferably a methylene group or an ethylene group.

A^(a30) is preferably a single bond, *—CO—O— or *—CO—O-A^(a52)-CO—O—,more preferably a single bond, *—CO—O— or *—CO—O—CH₂—CO—O—, and stillmore preferably a single bond or *—CO—O—.

mb is preferably 0, 1 or 2, more preferably 0 or 1, and still morepreferably 0.

The hydroxy group is preferably bonded at the m-position or thep-position of the benzene ring. When having two or more hydroxy groups,two hydroxy groups are preferably bonded at the m-position and thep-position, respectively.

Examples of the structural unit (a2-A) include structural units derivedfrom the monomers mentioned in JP 2010-204634 A and JP 2012-12577 A.

Examples of the structural unit (a2-A) include structural unitsrepresented by formula (a2-2-1) to formula (a2-2-24), and a structuralunit in which a methyl group corresponding to R^(a50) in the structuralunit (a2-A) is substituted with a hydrogen atom, a halogen atom, ahaloalkyl group or other alkyl groups in structural units represented byformula (a2-2-1) to formula (a2-2-24). The structural unit (a2-A) ispreferably a structural unit represented by formula (a2-2-1) to astructural unit represented by formula (a2-2-4), a structural unitrepresented by formula (a2-2-6), a structural unit represented byformula (a2-2-8), structural units represented by formula (a2-2-12) toformula (a2-2-18), and a structural unit in which a methyl groupcorresponding to R^(a50) in the structural unit (a2-A) is substitutedwith a hydrogen atom in structural units represented by formula (a2-2-1)to formula (a2-2-4), a structural unit represented by formula (a2-2-6),a structural unit represented by formula (a2-2-8) and structural unitsrepresented by formula (a2-2-12) to formula (a2-2-18), more preferably astructural unit represented by formula (a2-2-3), a structural unitrepresented by formula (a2-2-4), a structural unit represented byformula (a2-2-8), structural units represented by formula (a2-2-12) toformula (a2-2-14), a structural unit represented by formula (a2-2-18),and a structural unit in which a methyl group corresponding to R^(a50)in the structural unit (a2-A) is substituted with a hydrogen atom in astructural unit represented by formula (a2-2-3), a structural unitrepresented by formula (a2-2-4), a structural unit represented byformula (a2-2-8), structural units represented by formula (a2-2-12) toformula (a2-2-14) and a structural unit represented by formula(a2-2-18), and still more preferably a structural unit represented byformula (a2-2-3), a structural unit represented by formula (a2-2-4), astructural unit represented by formula (a2-2-8), and a structural unitin which a methyl group corresponding to R^(a) so in the structural unit(a2-A) is substituted with a hydrogen atom in a structural unitrepresented by formula (a2-2-3), a structural unit represented byformula (a2-2-4) and a structural unit represented by formula (a2-2-8).

When the structural unit (a2-A) is contained in the resin (A) or thelike, the content of the structural unit (a2-A) is preferably 5 mol % ormore, more preferably It is 10 mol % or e, more preferably 15 mol ormore, and still more preferably 20 mol % or more. Also, it is preferably80 mol % or less, more preferably 70 mol % or less, and still morepreferably 65 mol % or less. Specifically, it is preferably 5 to 80 mol,more preferably 10 to 70 mol %, even more preferably 15 to 65 mol, stillmore preferably 20 to 65 mol %.

The structural unit (a2-A) can be included in the resin (A) bypolymerizing, for example, with a structural unit (a1-4) and treatingwith an acid such as p-toluenesulfonic acid. The structural unit (a2-A)can also be included in the resin (A) by polymerizing withacetoxystyrene and treating with an alkali such as tetramethylammoniumhydroxide.

Examples of the structural unit having an alcoholic hydroxy group in thestructural unit (a2) include a structural unit represented by formula(a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).

In formula (a2-1),

L^(a3) represents —O— or *—O—(CH₂)_(k2)—CO—O—,

k2 represents an integer of 1 to 7, and * represents a bonding site to—CO—,

R^(a14) represents a hydrogen atom or a methyl group,

R^(a15) and R^(a16) each independently represent a hydrogen atom, amethyl group or a hydroxy group, and

o1 represents an integer of 0 to 10.

In formula (a2-1), L^(a3) is preferably —O— or —O—(CH₂)_(f1)—CO—O— (f1represents an integer of 1 to 4), and more preferably —O—,

R^(a14) is preferably a methyl group,

R^(a15) is preferably a hydrogen atom,

R^(a16) is preferably a hydrogen atom or a hydroxy group, and

o1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

The structural unit (a2-1) includes, for example, structural unitsderived from the monomers mentioned in JP 2010-204646 A. A structuralunit represented by any one of formula (a2-1-1) to formula (a2-1-6) ispreferable, a structural unit represented by any one of formula (a2-1-1)to formula (a2-1-4) is more preferable, and a structural unitrepresented by formula (a2-1-1) or formula (a2-1-3) is still morepreferable.

When the resin (A) or the like contains the structural unit (a2-1), thecontent is usually 1 mol % or more, preferably 2 mol % or more, based onthe total structural units of the resin (A) or the like. Also, it is 45mol % or less, preferably 40 mol % or less, more preferably 35 mol % orless, still more preferably 20 mol % or less, and even more preferably10 mol % or less. Specifically, it is 1 to 45 mol %, preferably 1 to 40mol %, more preferably 1 to 35 mol %, still more preferably 1 to 20 mol%, still more preferably 1˜10 mol %.

<Structural Unit (a3)>

The lactone ring possessed by the structural unit (a3) may be amonocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ringor a δ-valerolactone ring, or a fused ring of a monocyclic lactone ringand the other ring. Preferably, a γ-butyrolactone ring, anadamantanelactone ring or a bridged ring including a γ-butyrolactonering structure (e.g. a structural unit represented by the followingformula (a3-2)) is exemplified.

The structural unit (a3) is preferably a structural unit represented byformula (a3-1), formula (a3-2), formula (a3-3) or formula (a3-4). Thesestructural units may be included alone, or two or more structural unitsmay be included:

wherein, in formula (a3-1), formula (a3-2), formula (a3-3) and formula(a3-4),

L^(a4), L^(a5) and L^(a6) each independently represent —O— or a grouprepresented by *—O—(CH₂)_(k3)—CO—O— (k3 represents an integer of 1 to7),

L^(a7) represents —O—, *—O-L^(a8)-O—, *—O-L^(a8)-CO—O—,*—O-L^(a8)-CO—O-L^(a9)-CO—O— or *—O-L^(a8)-O—CO-L^(a9)-O—,

L^(a8) and L^(a9) each independently represent an alkanediyl grouphaving 1 to 6 carbon atoms,

* represents a bonding site to a carbonyl group,

R^(a18), R^(a19) and R^(a20) each independently represent a hydrogenatom or a methyl group,

R^(a24) represents an alkyl group having 1 to 6 carbon atoms which mayhave a halogen atom, a hydrogen atom or a halogen atom,

X^(a3) represents —CH₂— or an oxygen atom,

R^(a21) represents an aliphatic hydrocarbon group having 1 to 4 carbonatoms,

R^(a22), R^(a23) and R^(a25) each independently represent a carboxygroup, a cyano group or an aliphatic hydrocarbon group having 1 to 4carbon atoms,

p1 represents an integer of 0 to 5,

q1 represents an integer of 0 to 3,

r1 represents an integer of 0 to 3,

w1 represents an integer of 0 to 8, and

when p1, q1, r1 and/or w1 is/are 2 or more, a plurality of R^(a21),R^(a22), R^(a23) and/or R^(a25) may be the same or different from eachother.

Examples of the aliphatic hydrocarbon group in R^(a21), R^(a22), R^(a23)and R^(a25) include alkyl groups such as a methyl group, an ethyl group,a propyl group, an isopropyl group, a butyl group, a sec-butyl group anda tert-butyl group.

Examples of the halogen atom in R^(a24) include a fluorine atom, achlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group in R^(a24) include a methyl group, an ethylgroup, a propyl group, an isopropyl group, a butyl group, a sec-butylgroup, a tert-butyl group, a pentyl group and a hexyl group, and thealkyl group is preferably an alkyl group having 1 to 4 carbon atoms, andmore preferably a methyl group or an ethyl group.

Examples of the alkyl group having a halogen atom in R^(a24) include atrifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group,a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butylgroup, a perfluorotert-butyl group, a perfluoropentyl group, aperfluorohexyl group, a trichloromethyl group, a tribromomethyl group, atriiodomethyl group and the like.

Examples of the alkanediyl group in L^(a8) and L^(a9) include amethylene group, an ethylene group, a propane-1,3-diyl group, apropane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diylgroup, a hexane-1,6-diyl group, a butane-1,3-diyl group, a2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, apentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group.

In formula (a3-1) to formula (a3-3), preferably, L^(a4) to L^(a6) areeach independently —O— or a group in which k3 is an integer of 1 to 4 in*—O—(CH₂)_(k3)—CO—O—, more preferably —O— and *—O—CH₂—CO—O—, and stillmore preferably an oxygen atom,

R^(a18) to R^(a21) are preferably a methyl group,

preferably, R^(a22) and R^(a23) are each independently a carboxy group,a cyano group or a methyl group, and

preferably, p1, q1 and r1 are each independently an integer of 0 to 2,and more preferably 0 or 1.

In formula (a3-4), R^(a24) is preferably a hydrogen atom or an alkylgroup having 1 to 4 carbon atoms, more preferably a hydrogen atom, amethyl group or an ethyl group, and still more preferably a hydrogenatom or a methyl group,

R^(a25) is preferably a carboxy group, a cyano group or a methyl group,

L^(a7) is preferably —O— or *—O-L^(a8)-CO—O—, and more preferably —O—,—O—CH₂—CO—O— or —O—C₂H₄—CO—O—, and

w1 is preferably an integer of 0 to 2, and more preferably 0 or 1.

Particularly, formula (a3-4) is preferably formula (a3-4)′:

wherein R^(a24) and L^(a7) are the same as defined above.

Examples of the structural unit (a3) include structural units derivedfrom the monomers mentioned in JP 2010-204646 A, the monomers mentionedin JP 2000-122294 A and the monomers mentioned in JP 2012-41274 A. Thestructural unit (a3) is preferably a structural unit represented by anyone of formula (a3-1-1), formula (a3-1-2), formula (a3-2-1), formula(a3-2-2), formula (a3-3-1), formula (a3-3-2) and formula (a3-4-1) toformula (a3-4-12), and structural units in which methyl groupscorresponding to R^(a18), R^(a19), R^(a20) and R^(a24) in formula (a3-1)to formula (a3-4) are substituted with hydrogen atoms in the abovestructural units.

When the resin (A) or the like contains the structural unit (a3), thetotal content thereof is usually 1 mol % or more, preferably 3 mol ormore, based on the total structural units of the resin (A). morepreferably 5 mol % or more, still more preferably 10 mol % or more.Also, it is 70 mol % or less, preferably 65 mol % or less, and morepreferably 60 mol % or less. Specifically, it is 1 to 70 mol, preferably3 to 65 mol, more preferably 5 to 60 mol %

Further, the content of structural unit (a3-1) structural unit (a3-2),structural unit (a3-3) or structural unit (a3-4) is On the other hand,it is preferably 1 mol % or more, more preferably 3 mol % or more, andstill more preferably 5 mol % or more. Also, it is preferably 60 mol orless, more preferably 55 mol % or less, and still more preferably 50 mol% or less. Specifically, it is preferably 1 to 60 mol %, more preferably3 to 50 mol %, and even more preferably 5 to 50 mol %.¥

<Structural Unit (a4)>

Examples of the structural unit (a4) include the following structuralunit:

wherein, in formula (a4),

R⁴¹ represents a hydrogen atom or a methyl group, and

R⁴² represents a saturated hydrocarbon group having 1 to 24 carbon atomswhich has a halogen atom, and —CH₂— included in the saturatedhydrocarbon group may be replaced by —O— or —CO—.

Examples of the chain saturated hydrocarbon group represented by R⁴²include a chain saturated hydrocarbon group and a monocyclic orpolycyclic alicyclic saturated hydrocarbon group, and groups formed bycombining these groups.

Examples of the chain saturated hydrocarbon group include a methylgroup, an ethyl group, a propyl group, a butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a decyl group, a dodecylgroup, a pentadecyl group, a hexadecyl group, a heptadecyl group and anoctadecyl group.

Examples of the monocyclic or polycyclic alicyclic saturated hydrocarbongroup include cycloalkyl groups such as a cyclopentyl group, acyclohexyl group, a cycloheptyl group and a cyclooctyl group; andpolycyclic alicyclic saturated hydrocarbon groups such as adecahydronaphthyl group, an adamantyl group, a norbornyl group, and thefollowing groups (* represents a bonding site).

Examples of the group formed by combination include groups formed bycombining one or more alkyl groups or one or more alkanediyl groups withone or more alicyclic saturated hydrocarbon groups, and include analkanediyl group-alicyclic saturated hydrocarbon group, an alicyclicsaturated hydrocarbon group-alkyl group, an alkanediyl group-alicyclicsaturated hydrocarbon group-alkyl group and the like.

Examples of the structural unit (a4) include a structural unitrepresented by formula (a4-0), a structural unit represented by formula(a4-1), and a structural unit represented by formula (a4-4):

wherein, in formula (a4-0),

R⁵⁴ represents a hydrogen atom or a methyl group,

L^(4a) represents a single bond or an alkanediyl group having 1 to 4carbon atoms,

L^(3a) represents a perfluoroalkanediyl group having 1 to 8 carbon atomsor a perfluorocycloalkanediyl group having 3 to 12 carbon atoms, and

R⁶⁴ represents a hydrogen atom or a fluorine atom.

Examples of the alkanediyl group in L^(4a) include linear alkanediylgroups such as a methylene group, an ethylene group, a propane-1,3-diylgroup and a butane-1,4-diyl group; and branched alkanediyl groups suchas an ethane-1,1-diyl group, a propane-1,2-diyl group, a butane-1,3-diylgroup, a 2-methylpropane-1,3-diyl group and a 2-methylpropane-1,2-diylgroup.

Examples of the perfluoroalkanediyl group in L^(3a) include adifluoromethylene group, a perfluoroethylene group, aperfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group,a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2-diyl group, aperfluorobutane-1,4-diyl group, a perfluorobutane-2,2-diyl group, aperfluorobutane-1,2-diyl group, a perfluoropentane-1,5-diyl group, aperfluoropentane-2,2-diyl group, a perfluoropentane-3,3-diyl group, aperfluorohexane-1,6-diyl group, a perfluorohexane-2,2-diyl group, aperfluorohexane-3,3-diyl group, a perfluoroheptane-1,7-diyl group, aperfluoroheptane-2,2-diyl group, a perfluoroheptane-3,4-diyl group, aperfluoroheptane-4,4-diyl group, a perfluorooctane-1,8-diyl group, aperfluorooctane-2,2-diyl group, a perfluorooctane-3,3-diyl group, aperfluorooctane-4,4-diyl group and the like.

Examples of the perfluorocycloalkanediyl group in L^(3a) include aperfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, aperfluorocycloheptanediyl group, a perfluoroadamantanediyl group and thelike.

L^(4a) is preferably a single bond, a methylene group or an ethylenegroup, and more preferably a single bond or a methylene group.

L^(3a) is preferably a perfluoroalkanediyl group having 1 to 6 carbonatoms, and more preferably a perfluoroalkanediyl group having 1 to 3carbon atoms.

Examples of the structural unit (a4-0) include the following structuralunits, and structural units in which a methyl group corresponding to R⁵⁴in the structural unit (a4-0) in the following structural units issubstituted with a hydrogen atom:

Examples of the structural unit (a4) include a structural unitrepresented by formula (a4-1):

wherein, in formula (a4-1),

R^(a41) represents a hydrogen atom or a methyl group,

R^(a42) represents a saturated hydrocarbon group having 1 to 20 carbonatoms which may have a substituent, and —CH₂— included in the saturatedhydrocarbon group may be replaced by —O— or —CO—,

A^(a41) represents an alkanediyl group having 1 to 6 carbon atoms whichmay have a substituent or a group represented by formula (a-g1), inwhich at least one of A^(a41) and R^(a42) has, as a substituent, ahalogen atom (preferably a fluorine atom):

[in which, in formula (a-g1),

s represents 0 or 1,

A^(a42) and A^(a44) each independently represent a divalent saturatedhydrocarbon group having 1 to 5 carbon atoms which may have asubstituent,

A^(a43) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 5 carbon atoms which may have a substituent,

X^(a41) and X^(a42) each independently represent —O—, —CO—, —CO—O— or—O—CO—,

in which the total number of carbon atoms of A^(a42), A^(a43), A^(a44),X^(a41) and X^(a42) is 7 or less], and

* represents a bonding site and * at the right side represents a bondingsite to —O—CO—R^(a42).

Examples of the saturated hydrocarbon group in R^(a42) include a chainhydrocarbon group and a monocyclic or polycyclic alicyclic hydrocarbongroup, and groups formed by combining these groups.

Examples of the chain hydrocarbon group include a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, a hexyl group, aheptyl group, an octyl group, a decyl group, a dodecyl group, apentadecyl group, a hexadecyl group, a heptadecyl group and an octadecylgroup.

Examples of the monocyclic or polycyclic saturated alicyclic hydrocarbongroup include cycloalkyl groups such as a cyclopentyl group, acyclohexyl group, a cycloheptyl group and a cyclooctyl group; andpolycyclic alicyclic hydrocarbon groups such as a decahydronaphthylgroup, an adamantyl group, a norbornyl group, and the following groups(* represents a bonding site).

Examples of the group formed by combination include groups formed bycombining one or more alkyl groups or one or more alkanediyl groups withone or more saturated alicyclic hydrocarbon groups, for example, an-alkanediyl group-saturated alicyclic hydrocarbon group, a -saturatedalicyclic hydrocarbon group-alkyl group, an -alkanediyl group-saturatedalicyclic hydrocarbon group-alkyl group and the like.

Examples of the substituent possessed by R^(a42) include at least oneselected from the group consisting of a halogen atom and the groupconsisting of the group represented by formula (a-g3). Examples of thehalogen atom include a fluorine atom, a chlorine atom, a bromine atomand an iodine atom, and a fluorine atom is preferable:

—X^(a43)-A^(a45)  (a-g3)

wherein, in formula (a-g3),

X^(a43) represents an oxygen atom, a carbonyl group, *—O—CO— or *—CO—O—,

A^(a45) represents a saturated hydrocarbon group having 1 to 17 carbonatoms which may have a halogen atom, and

* represents a bonding site to R^(a42).

In R^(a42)—X^(a43)-A^(a45), when R^(a42) has no halogen atom, A^(a45)represents a saturated hydrocarbon group having 1 to 17 carbon atomshaving at least one halogen atom.

Examples of the saturated hydrocarbon group in A^(a45) include alkylgroups such as a methyl group, an ethyl group, a propyl group, a butylgroup, a pentyl group, a hexyl group, a heptyl group, an octyl group, adecyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, aheptadecyl group and an octadecyl group; monocyclic alicyclichydrocarbon groups such as a cyclopentyl group, a cyclohexyl group, acycloheptyl group and a cyclooctyl group; and polycyclic alicyclichydrocarbon groups such as a decahydronaphthyl group, an adamantylgroup, a norbornyl group and the following groups (* represents abonding site).

Examples of the group formed by combination include groups obtained bycombining one or more alkyl groups or one or more alkanediyl groups withone or more alicyclic hydrocarbon groups, for example, an -alkanediylgroup-alicyclic hydrocarbon group, an -alicyclic hydrocarbon group-alkylgroup, an -alkanediyl group-alicyclic hydrocarbon group-alkyl group andthe like.

R^(a42) is preferably a saturated hydrocarbon group which may have ahalogen atom, and more preferably an alkyl group having a halogen atomand/or a saturated hydrocarbon group having a group represented byformula (a-g3).

When R^(a42) is a saturated hydrocarbon group having a halogen atom, asaturated hydrocarbon group having a fluorine atom is preferable, aperfluoroalkyl group or a perfluorocycloalkyl group is more preferable,a perfluoroalkyl group having 1 to 6 carbon atoms is still morepreferable, and a perfluoroalkyl group having 1 to 3 carbon atoms isparticularly preferable. Examples of the perfluoroalkyl group include aperfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group,a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group,a perfluoroheptyl group and a perfluorooctyl group. Examples of theperfluorocycloalkyl group include a perfluorocyclohexyl group and thelike.

When R^(a42) is a saturated hydrocarbon group having a group representedby formula (a-g3), the total number of carbon atoms of R^(a42) ispreferably 15 or less, and more preferably 12 or less, including thenumber of carbon atoms included in the group represented by formula(a-g3). When having the group represented by formula (a-g3) as thesubstituent, the number thereof is preferably 1.

When R^(a42) is a saturated hydrocarbon group having the grouprepresented by formula (a-g3), R^(a42) is still more preferably a grouprepresented by formula (a-g2):

*-A^(a46)-X^(a44)-A^(a47)  (a-g2)

wherein, in formula (a-g2),

A^(a46) represents a divalent saturated hydrocarbon group having 1 to 17carbon atoms which may have a halogen atom,

X^(a44) represents **—O—CO— or **—CO—O— (** represents a bonding site toA^(a46)),

A^(a47) represents a saturated hydrocarbon group having 1 to 17 carbonatoms which may have a halogen atom,

the total number of carbon atoms of A^(a46), A^(a47) and X^(a44) is 18or less, and at least one of A^(a46) and A^(a47) has at least onehalogen atom, and

* represents a bonding site to a carbonyl group.

The number of carbon atoms of the saturated hydrocarbon group as forA^(a46) is preferably 1 to 6, and more preferably 1 to 3.

The number of carbon atoms of the saturated hydrocarbon group as forA^(a47) is preferably 4 to 15, and more preferably 5 to 12, and A^(a47)is still more preferably a cyclohexyl group or an adamantyl group.

Preferred structures of the group represented by formula (a-g2) are thefollowing structures (* represents a bonding site to a carbonyl group).

Examples of the alkanediyl group in A^(a41) include linear alkanediylgroups such as a methylene group, an ethylene group, a propane-1,3-diylgroup, a butane-1,4-diyl group, a pentane-1,5-diyl group and ahexane-1,6-diyl group; and branched alkanediyl groups such as apropane-1,2-diyl group, a butane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a 1-methylbutane-1,4-diyl group and a2-methylbutane-1,4-diyl group.

Examples of the substituent in the alkanediyl group represented byA^(a41) include a hydroxy group and an alkoxy group having 1 to 6 carbonatoms.

A^(a41) is preferably an alkanediyl group having 1 to 4 carbon atoms,more preferably an alkanediyl group having 2 to 4 carbon atoms, andstill more preferably an ethylene group.

Examples of the divalent saturated hydrocarbon group represented byA^(a42), A^(a43) and A^(a44) in the group represented by formula (a-g1)include a linear or branched alkanediyl group and a monocyclic divalentalicyclic saturated hydrocarbon group, and divalent saturatedhydrocarbon groups formed by combining an alkanediyl group and adivalent alicyclic saturated hydrocarbon group. Specific examplesthereof include a methylene group, an ethylene group, a propane-1,3-diylgroup, a propane-1,2-diyl group, a butane-1,4-diyl group, a1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group and the like.

Examples of the substituent of the divalent saturated hydrocarbon grouprepresented by A^(a42), A^(a43) and A^(a44) include a hydroxy group andan alkoxy group having 1 to 6 carbon atoms.

s is preferably 0.

In the group represented by formula (a-g1), examples of the group inwhich X^(a42) is —O—, —CO—, —CO—O— or —O—CO-include the followinggroups. In the following exemplification, * and ** each represent abonding site, and ** represents a bonding site to —O—CO—R^(a42).

Examples of the structural unit represented by formula (a4-1) includethe following structural units, and structural units in which a methylgroup corresponding to A^(a41) in the structural unit represented byformula (a4-1) in the following structural units is substituted with ahydrogen atom.

Examples of the structural unit (a4) include a structural unitrepresented by formula (a4-2) and a structural unit represented byformula (a4-3):

wherein, in formula (a4-2),

R^(f5) represents a hydrogen atom or a methyl group,

L⁴⁴ represents an alkanediyl group having 1 to 6 carbon atoms, and —CH₂—included in the alkanediyl group may be replaced by —O— or —CO—,

R^(f6) represents a saturated hydrocarbon group having 1 to 20 carbonatoms having a fluorine atom, and

the upper limit of the total number of carbon atoms as for L⁴⁴ andR^(f6) is 21.

Examples of the alkanediyl group having 1 to 6 carbon atoms as for L⁴⁴include the same groups as mentioned for A^(a41).

Examples of the saturated hydrocarbon group as for R^(f6) include thesame groups as mentioned for R⁴².

The alkanediyl group in L⁴⁴ is preferably an alkanediyl group having 2to 4 carbon atoms, and more preferably an ethylene group.

The structural unit represented by formula (a4-2) includes, for example,structural units represented by formula (a4-1-1) to formula (a4-1-11). Astructural unit in which a methyl group corresponding to R^(f5) in thestructural unit (a4-2) is substituted with a hydrogen atom is alsoexemplified as the structural unit represented by formula (a4-2).

wherein, in formula (a4-3),

R^(f7) represents a hydrogen atom or a methyl group,

L⁵ represents an alkanediyl group having 1 to 6 carbon atoms,

A^(f13) represents a divalent saturated hydrocarbon group having 1 to 18carbon atoms which may have a fluorine atom,

X^(f12) represents *—O—CO— or *—CO—O— (* represents a bonding site toA^(f13)),

A^(f14) represents a saturated hydrocarbon group having 1 to 17 carbonatoms which may have a fluorine atom, and

at least one of A^(f13) and A^(f14) has a fluorine atom, and the upperlimit of the total number of carbon atoms of L⁵, A^(f13) and A^(f14) is20.

Examples of the alkanediyl group in L⁵ include those which are the sameas mentioned as for the alkanediyl group as for A^(a41).

The divalent saturated hydrocarbon group which may have a fluorine atomin A^(f13) is preferably a divalent chain saturated hydrocarbon groupwhich may have a fluorine atom and a divalent alicyclic saturatedhydrocarbon group which may have a fluorine atom, and more preferably aperfluoroalkanediyl group.

Examples of the divalent chain saturated hydrocarbon group which mayhave a fluorine atom include alkanediyl groups such as a methylenegroup, an ethylene group, a propanediyl group, a butanediyl group and apentanediyl group; and perfluoroalkanediyl groups such as adifluoromethylene group, a perfluoroethylene group, aperfluoropropanediyl group, a perfluorobutanediyl group and aperfluoropentanediyl group.

The divalent alicyclic saturated hydrocarbon group which may have afluorine atom may be either monocyclic or polycyclic. Examples of themonocyclic group include a cyclohexanediyl group and aperfluorocyclohexanediyl group. Examples of the polycyclic group includean adamantanediyl group, a norbornanediyl group, aperfluoroadamantanediyl group and the like.

Examples of the saturated hydrocarbon group and the saturatedhydrocarbon group which may have a fluorine atom as for A^(f14) includethe same groups as mentioned as for R^(a42). Of these groups, preferredare fluorinated alkyl groups such as a trifluoromethyl group, adifluoromethyl group, a methyl group, a perfluoroethyl group, a2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethylgroup, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, apropyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutylgroup, a butyl group, a perfluoropentyl group, a2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group,a perfluorohexyl group, a heptyl group, a perfluoroheptyl group, anoctyl group and a perfluorooctyl group; a cyclopropylmethyl group, acyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, acyclohexyl group, a perfluorocyclohexyl group, an adamantyl group, anadamantylmethyl group, an adamantyldimethyl group, a norbornyl group, anorbornylmethyl group, a perfluoroadamantyl group, aperfluoroadamantylmethyl group and the like.

In formula (a4-3), L⁵ is preferably an ethylene group.

The divalent saturated hydrocarbon group as for A^(f13) is preferably agroup including a divalent chain saturated hydrocarbon group having 1 to6 carbon atoms and a divalent alicyclic saturated hydrocarbon grouphaving 3 to 12 carbon atoms, and more preferably a divalent chainsaturated hydrocarbon group having 2 to 3 carbon atoms.

The saturated hydrocarbon group as for A^(f14) is preferably a groupwhich has a chain saturated hydrocarbon group having 3 to 12 carbonatoms and an alicyclic saturated hydrocarbon group having 3 to 12 carbonatoms, and more preferably a group which has a chain saturatedhydrocarbon group having 3 to 10 carbon atoms and an alicyclic saturatedhydrocarbon group having 3 to 10 carbon atoms. Of these groups, A^(f14)is preferably a group which has an alicyclic saturated hydrocarbon grouphaving 3 to 12 carbon atoms, and more preferably a cyclopropylmethylgroup, a cyclopentyl group, a cyclohexyl group, a norbornyl group and anadamantyl group.

The structural unit represented by formula (a4-3) includes, for example,structural units represented by formula (a4-1′-1) to formula (a4-1′-11).A structural unit in which a methyl group corresponding to R^(f7) in thestructural unit (a4-3) is substituted with a hydrogen atom is alsoexemplified as the structural unit represented by formula (a4-3).

It is also possible to exemplify, as the structural unit (a4), astructural unit represented by formula (a4-4):

wherein, in formula (a4-4),

R^(f21) represents a hydrogen atom or a methyl group,

A^(f21) represents —(CH₂)_(j1)—, —(CH₂)_(j2)—O—(CH₂)_(j3)— or—(CH₂)_(j4)—CO—O— (CH₂)_(j5)—,

j1 to j5 each independently represent an integer of 1 to 6, and

R^(f22) represents a saturated hydrocarbon group having 1 to 10 carbonatoms having a fluorine atom.

Examples of the saturated hydrocarbon group of R^(f22) include thosewhich are the same as the saturated hydrocarbon group represented byR^(a42). R^(f22) is preferably an alkyl group having 1 to 10 carbonatoms which has a fluorine atom or an alicyclic hydrocarbon group having1 to 10 carbon atoms which has a fluorine atom, more preferably an alkylgroup having 1 to 10 carbon atoms which has a fluorine atom, and stillmore preferably an alkyl group having 1 to 6 carbon atoms which has afluorine atom.

In formula (a4-4), A^(f21) is preferably —(CH₂)_(j1)—, more preferablyan ethylene group or a methylene group, and still more preferably amethylene group.

The structural unit represented by formula (a4-4) includes, for example,the following structural units and structural units in which a methylgroup corresponding to R^(f21) in the structural unit (a4-4) issubstituted with a hydrogen atom in structural units represented by thefollowing formulas.

When the resin (A) includes the structural unit (a4), the content ispreferably 1 to 20 mol %, more preferably 2 to 15 mol %, and still morepreferably 3 to 10 mol %, based on all structural units of the resin(A).

<Structural Unit (a5)>

Examples of a non-leaving hydrocarbon group possessed by the structuralunit (a5) include groups having a linear, branched or cyclic hydrocarbongroup. Of these, the structural unit (a5) is preferably a group havingan alicyclic hydrocarbon group.

The structural unit (a5) includes, for example, a structural unitrepresented by formula (a5-1):

wherein, in formula (a5-1),

R⁵¹ represents a hydrogen atom or a methyl group,

R⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbonatoms, and a hydrogen atom included in the alicyclic hydrocarbon groupmay be substituted with an aliphatic hydrocarbon group having 1 to 8carbon atoms, and

L⁵⁵ represents a single bond or a divalent saturated hydrocarbon grouphaving 1 to 18 carbon atoms, and —CH₂— included in the saturatedhydrocarbon group may be replaced by —O— or —CO—.

The alicyclic hydrocarbon group in R⁵² may be either monocyclic orpolycyclic. The monocyclic alicyclic hydrocarbon group includes, forexample, a cyclopropyl group, a cyclobutyl group, a cyclopentyl groupand a cyclohexyl group. The polycyclic alicyclic hydrocarbon groupincludes, for example, an adamantyl group and a norbornyl group.

The aliphatic hydrocarbon group having 1 to 8 carbon atoms includes, forexample, alkyl groups such as a methyl group, an ethyl group, a propylgroup, an isopropyl group, a butyl group, a sec-butyl group, atert-butyl group, a pentyl group, a hexyl group, an octyl group and a2-ethylhexyl group.

Examples of the alicyclic hydrocarbon group having a substituentincludes a 3-methyladamantyl group and the like.

R⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3to 18 carbon atoms, and more preferably an adamantyl group, a norbornylgroup or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group in L⁵⁵ include adivalent chain saturated hydrocarbon group and a divalent alicyclicsaturated hydrocarbon group, and a divalent chain saturated hydrocarbongroup is preferable.

The divalent chain saturated hydrocarbon group includes, for example,alkanediyl groups such as a methylene group, an ethylene group, apropanediyl group, a butanediyl group and a pentanediyl group.

The divalent alicyclic saturated hydrocarbon group may be eithermonocyclic or polycyclic. Examples of the monocyclic alicyclic saturatedhydrocarbon group include cycloalkanediyl groups such as acyclopentanediyl group and a cyclohexanediyl group. Examples of thepolycyclic divalent alicyclic saturated hydrocarbon group include anadamantanediyl group and a norbornanediyl group.

The group in which —CH₂— included in the divalent saturated hydrocarbongroup represented by L⁵⁵ is replaced by —O— or —CO— includes, forexample, groups represented by formula (L1-1) to formula (L1-4). In thefollowing formulas, * and ** each represent a bonding site, and *represents a bonding site to an oxygen atom.

In formula (L1-1),

X^(x1) represents *—O—CO— or *—CO—O— (* represents a bonding site toL^(x)i),

L^(x1) represents a divalent aliphatic saturated hydrocarbon grouphaving 1 to 16 carbon atoms,

L^(x2) represents a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 15 carbon atoms, and

the total number of carbon atoms of L^(x1) and L^(x2) is 16 or less.

In formula (L1-2),

L^(x3) represents a divalent aliphatic saturated hydrocarbon grouphaving 1 to 17 carbon atoms,

L^(x4) represents a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 16 carbon atoms, and

the total number of carbon atoms of L^(x3) and L^(x4) is 17 or less.

In formula (L1-3),

L^(x5) represents a divalent aliphatic saturated hydrocarbon grouphaving 1 to 15 carbon atoms,

L^(x6) and L^(x7) each independently represent a single bond or adivalent aliphatic saturated hydrocarbon group having 1 to 14 carbonatoms, and

the total number of carbon atoms of L^(x5), L^(x6) and L^(x7) is 15 orless.

In formula (L1-4),

L^(x8) and L^(x9) represent a single bond or a divalent aliphaticsaturated hydrocarbon group having 1 to 12 carbon atoms,

W^(x1) represents a divalent alicyclic saturated hydrocarbon grouphaving 3 to 15 carbon atoms, and

the total number of carbon atoms of L^(x8), L^(x9) and W^(x1) is 15 orless.

L^(x1) is preferably a divalent aliphatic saturated hydrocarbon grouphaving 1 to 8 carbon atoms, and more preferably a methylene group or anethylene group.

L^(x2) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms, and more preferably asingle bond.

L^(x3) is preferably a divalent aliphatic saturated hydrocarbon grouphaving 1 to 8 carbon atoms.

L^(x4) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms.

L^(x5) is preferably a divalent aliphatic saturated hydrocarbon grouphaving 1 to 8 carbon atoms, and more preferably a methylene group or anethylene group.

L^(x6) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms, and more preferably amethylene group or an ethylene group.

L^(x7) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms.

L^(x8) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms, and more preferably asingle bond or a methylene group.

L^(x9) is preferably a single bond or a divalent aliphatic saturatedhydrocarbon group having 1 to 8 carbon atoms, and more preferably asingle bond or a methylene group.

W^(x1) is preferably a divalent alicyclic saturated hydrocarbon grouphaving 3 to 10 carbon atoms, and more preferably a cyclohexanediyl groupor an adamantanediyl group.

The group represented by formula (L1-1) includes, for example, thefollowing divalent groups.

The group represented by formula (L1-2) includes, for example, thefollowing divalent groups.

The group represented by formula (L1-3) includes, for example, thefollowing divalent groups.

The group represented by formula (L1-4) includes, for example, thefollowing divalent groups.

L⁵⁵ is preferably a single bond or a group represented by formula(L1-1).

Examples of the structural unit (a5-1) include the following structuralunits and structural units in which a methyl group corresponding to R⁵¹in the structural unit (a5-1) in the following structural units issubstituted with a hydrogen atom.

When the resin (A) includes the structural unit (a5), the content ispreferably 1 to 30 mol %, more preferably 2 to 20 mol %, and still morepreferably 3 to 15 mol %, based on all structural units of the resin(A).

<Structural Unit (a6)>

The structural unit (a6) is a structural unit having an —SO₂— group, andit is preferable to have an —SO₂— group in a side chain.

The structural unit having an —SO₂— group may have a linear structurehaving an —SO₂— group, a branched structure having an —SO₂— group, or acyclic structure (monocyclic and polycyclic structure) having an —SO₂—group. The structural unit is preferably a structural unit which has acyclic structure having an —SO₂— group, and more preferably a structuralunit which has a cyclic structure (sultone ring) having —SO₂—O—.

Examples of the sultone ring include rings represented by the followingformula (T¹-1), formula (T¹-2), formula (T¹-3) and formula (T¹-4). Thebonding site can be any position. The sultone ring may be monocyclic,and is preferably polycyclic. The polycyclic sultone ring means abridged ring which has —SO₂—O— as an atomic group constituting the ring,and examples thereof include rings represented by formula (T¹-1) andformula (T¹-2). The sultone ring may have, as the atomic groupconstituting the ring, a heteroatom, in addition to —SO₂—O—, like thering represented by formula (T¹-2). Examples of the heteroatom includean oxygen atom, a sulfur atom or a nitrogen atom, and an oxygen atom ispreferable.

The sultone ring may have a substituent, and examples of the substituentinclude an alkyl group having 1 to 12 carbon atoms which may have ahalogen atom or a hydroxy group, a halogen atom, a hydroxy group, acyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl grouphaving 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbonatoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12carbon atoms and an alkylcarbonyl group having 2 to 4 carbon atoms.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

Examples of the alkyl group include a methyl group, an ethyl group, apropyl group, a butyl group, a pentyl group, a hexyl group, an octylgroup and a decyl group, and the alkyl group is preferably an alkylgroup having 1 to 6 carbon atoms, and more preferably a methyl group.

Examples of the alkyl group having a halogen atom include atrifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group,a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butylgroup, a perfluorotert-butyl group, a perfluoropentyl group, aperfluorohexyl group, a trichloromethyl group, a tribromomethyl groupand a triiodomethyl group, and a trifluoromethyl group is preferable.

Examples of the alkyl group having a hydroxy group include hydroxyalkylgroups such as a hydroxymethyl group and a 2-hydroxyethyl group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, apropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, aheptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxygroup.

Examples of the aryl group include a phenyl group, a naphthyl group, ananthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, ap-adamantylphenyl group, a tolyl group, a xylyl group, a cumyl group, amesityl group, a biphenyl group, a phenanthryl group, a2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.

Examples of the aralkyl group include a benzyl group, a phenethyl group,a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.

Examples of the alkoxycarbonyl group include groups in which an alkoxygroup is bonded with a carbonyl group, such as a methoxycarbonyl groupor an ethoxycarbonyl group, and preferably include an alkoxycarbonylgroup having 6 or less carbon atoms and more preferably include amethoxycarbonyl group.

Examples of the alkylcarbonyl group include an acetyl group, a propionylgroup and a butyryl group.

From the viewpoint that it is easy to produce a monomer from which thestructural unit (a6) is derived, a sultone ring having no substituent ispreferable.

The sultone ring is preferably a ring represented by the followingformula (T1′):

wherein, in formula (T1′),

X¹¹ represents an oxygen atom, a sulfur atom or a methylene group,

R⁴¹ represents an alkyl group having 1 to 12 carbon atoms which may havea halogen atom or a hydroxy group, a halogen atom, a hydroxy group, acyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl grouphaving 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbonatoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12carbon atoms, or an alkylcarbonyl group having 2 to 4 carbon atoms,

ma represents an integer of 0 to 9, and when ma is 2 or more, aplurality of R⁴¹ may be the same or different, and

the bonding site may be any position.

X¹¹ is preferably an oxygen atom or a methylene group, and morepreferably a methylene group.

Examples of R⁴¹ include those which are the same as the substituent ofthe above-mentioned sultone ring, and an alkyl group having 1 to 12carbon atoms which may have a halogen atom or a hydroxy group ispreferable.

ma is preferably 0 or 1, and more preferably 0.

Examples of the ring represented by formula (T1′) include the followingrings. The bonding site may be any position.

It is preferable that the structural unit having a sultone ring has thefollowing groups. * in the following groups represents a bonding site.

It is preferable that the structural unit having an —SO₂— group furtherhas a group derived from a polymerizable group. Examples of thepolymerizable group include a vinyl group, an acryloyl group, amethacryloyl group, an acryloyloxy group, a methacryloyloxy group, anacryloylamino group, a methacryloylamino group, an acryloylthio group, amethacryloylthio group and the like.

Particularly, the monomer from which the structural unit (a6) is derivedis preferably a monomer having an ethylenically unsaturated bond, andmore preferably a (meth)acrylic monomer.

The structural unit (a6) is preferably a structural unit represented byformula (a6-0):

wherein, in formula (a6-0), R^(x) represents an alkyl group having 1 to6 carbon atoms which may have a halogen atom, a hydrogen atom or ahalogen atom,

A^(xx) represents an oxygen atom, —N(R^(c))— or a sulfur atom,

A^(x) represents a single bond or a divalent saturated hydrocarbon grouphaving 1 to 18 carbon atoms, and —CH₂-included in the saturatedhydrocarbon group may be replaced by —O—, —CO— or —N(R^(d))—,

X¹¹, R⁴¹ and ma have the same meanings as above, and

R^(c) and R^(d) each independently represent a hydrogen atom or an alkylgroup having 1 to 6 carbon atoms.

Examples of the halogen atom as for R^(x) include a fluorine atom, achlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group as for R^(x) include a methyl group, anethyl group, an n-propyl group, an isopropyl group, an n-butyl group, asec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexylgroup, and an alkyl group having 1 to 4 carbon atoms is preferable, anda methyl group or an ethyl group is more preferable.

Examples of the alkyl group having a halogen atom as for R^(x) include atrifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group,a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butylgroup, a perfluorotert-butyl group, a perfluoropentyl group, aperfluorohexyl group, a trichloromethyl group, a tribromomethyl groupand a triiodomethyl group.

R^(x) is preferably a hydrogen atom or an alkyl group having 1 to 4carbon atoms, more preferably a hydrogen atom, a methyl group or anethyl group, and still more preferably a hydrogen atom or a methylgroup.

Examples of the divalent saturated hydrocarbon group as for A^(x)include a linear alkanediyl group, a branched alkanediyl group and amonocyclic or polycyclic divalent alicyclic saturated hydrocarbon group,and the divalent saturated hydrocarbon group may be those obtained bycombining two or more of these groups.

Specific examples thereof include linear alkanediyl groups such as amethylene group, an ethylene group, a propane-1,3-diyl group, apropane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diylgroup, a hexane-1,6-diyl group, a heptane-1,7-diyl group, anoctane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diylgroup, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, atridecane-1,13-diyl group, a tetradecane-1,14-diyl group, apentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, aheptadecane-1,17-diyl group, an ethane-1,1-diyl group, apropane-1,1-diyl group and a propane-2,2-diyl group;

branched alkanediyl groups such as a butane-1,3-diyl group, a2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, apentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group;

monocyclic divalent alicyclic saturated hydrocarbon groups which arecycloalkanediyl groups such as a cyclobutane-1,3-diyl group, acyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and acyclooctane-1,5-diyl group; and

polycyclic divalent alicyclic saturated hydrocarbon groups such as anorbornane-1,4-diyl group, a norbornane-2,5-diyl group, anadamantane-1,5-diyl group and an adamantane-2,6-diyl group.

Examples of the structural unit (a6-0) include the following structuralunits.

Of these, structural units represented by formula (a6-1), formula(a6-2), formula (a6-6), formula (a6-7), formula (a6-8) and formula(a6-12) are preferable, and structural units represented by formula(a6-1), formula (a6-2), formula (a6-7) and (a6-8) are more preferable.

When the resin (A) includes the structural unit (a6), the content ispreferably 1 to 50 mol %, more preferably 2 to 40 mol %, and still morepreferably 3 to 30 mol %, based on all structural units of the resin(A).

<Structural Unit (II)>

The resin (A) may further include a structural unit which is decomposedupon exposure to radiation to generate an acid (hereinafter sometimesreferred to as “structural unit (II)”). Specific examples of thestructural unit (II) include the structural units mentioned in JP2016-79235 A, and a structural unit having a sulfonate group or acarboxylate group and an organic cation in a side chain or a structuralunit having a sulfonio group and an organic anion in a side chain arepreferable.

The structural unit having a sulfonate group or a carboxylate group andan organic cation in a side chain is preferably a structural unitrepresented by formula (II-2-A′):

wherein, in formula (II-2-A′),

X^(III3) represents a divalent saturated hydrocarbon group having 1 to18 carbon atoms, —CH₂— included in the saturated hydrocarbon group maybe replaced by —O—, —S— or —CO—, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a halogen atom, analkyl group having 1 to 6 carbon atoms which may have a halogen atom, ora hydroxy group,

A^(x1) represents an alkanediyl group having 1 to 8 carbon atoms, and ahydrogen atom included in the alkanediyl group may be substituted with afluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms,

RA⁻ represents a sulfonate group or a carboxylate group,

R^(III3) represents a hydrogen atom, a halogen atom, or an alkyl grouphaving 1 to 6 carbon atoms which may have a halogen atom, and

ZA⁺ represents an organic cation.

Examples of the halogen atom represented by R^(III3) include a fluorineatom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have ahalogen atom represented by R^(III3) include those which are the same asthe alkyl group having 1 to 6 carbon atoms which may have a halogen atomrepresented by R^(a8).

Examples of the alkanediyl group having 1 to 8 carbon atoms representedby A^(x1) include a methylene group, an ethylene group, apropane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diylgroup, a hexane-1,6-diyl group, an ethane-1,1-diyl group, apropane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diylgroup, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a2-methylbutane-1,4-diyl group and the like.

Examples of the perfluoroalkyl group having 1 to 6 carbon atoms whichmay be substituted in A^(X1) include a trifluoromethyl group, aperfluoroethyl group, a perfluoropropyl group, a perfluoroisopropylgroup, a perfluorobutyl group, a perfluorosec-butyl group, aperfluorotert-butyl group, a perfluoropentyl group, a perfluorohexylgroup and the like.

Examples of the divalent saturated hydrocarbon group having 1 to 18carbon atoms represented by X^(III3) include a linear or branchedalkanediyl group, a monocyclic or a polycyclic divalent alicyclicsaturated hydrocarbon group, or a combination thereof.

Specific examples thereof include linear alkanediyl groups such as amethylene group, an ethylene group, a propane-1,3-diyl group, apropane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diylgroup, a hexane-1,6-diyl group, a heptane-1,7-diyl group, anoctane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diylgroup, an undecane-1,11-diyl group and a dodecane-1,12-diyl group;branched alkanediyl groups such as a butane-1,3-diyl group, a2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, apentane-1,4-diyl group and a 2-methylbutane-1,4-diyl group;cycloalkanediyl groups such as a cyclobutane-1,3-diyl group, acyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and acyclooctane-1,5-diyl group; and divalent polycyclic alicyclic saturatedhydrocarbon groups such as a norbornane-1,4-diyl group, anorbornane-2,5-diyl group, an adamantane-1,5-diyl group and anadamantane-2,6-diyl group.

Those in which —CH₂— included in the saturated hydrocarbon group arereplaced by —O—, —S— or —CO— include, for example, divalent groupsrepresented by formula (X1) to formula (X53). Before replacing —CH₂—included in the saturated hydrocarbon group by —O—, —S— or —CO—, thenumber of carbon atoms is 17 or less. In the following formulas, * and** represent a bonding site, and * represents a bond to A^(x1).

X³ represents a divalent saturated hydrocarbon group having 1 to 16carbon atoms.

X⁴ represents a divalent saturated hydrocarbon group having 1 to 15carbon atoms.

X⁵ represents a divalent saturated hydrocarbon group having 1 to 13carbon atoms.

X⁶ represents a divalent saturated hydrocarbon group having 1 to 14carbon atoms.

X⁷ represents a trivalent saturated hydrocarbon group having 1 to 14carbon atoms.

X⁸ represents a divalent saturated hydrocarbon group having 1 to 13carbon atoms.

Examples of ZA⁺ in formula (II-2-A′) include those which are the same asthe cation Z1⁺ in the salt represented by formula (B1).

The structural unit represented by formula (II-2-A′) is preferably astructural unit represented by formula (II-2-A):

wherein, in formula (II-2-A),

R^(III3), X^(III3) and ZA⁺ are the same as defined above,

z2A represents an integer of 0 to 6,

R^(III2) and R^(III4) each independently represent a hydrogen atom, afluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, andwhen z2A is 2 or more, a plurality of R^(III2) and R^(III4) may be thesame or different form each other, and

Q^(a) and Q^(b) each independently represent a fluorine atom or aperfluoroalkyl group having 1 to 6 carbon atoms.

Examples of the perfluoroalkyl group having 1 to 6 carbon atomsrepresented by R^(III2), R^(III4), Q^(a) and Q^(b) include those whichare the same as the perfluoroalkyl group having 1 to 6 carbon atomsrepresented by Q^(b1).

The structural unit represented by formula (II-2-A) is preferably astructural unit represented by formula (II-2-A-1):

wherein, in formula (II-2-A-1),

R^(III2), R^(III3), R^(III4), Q^(a), Q^(b) and ZA⁺ are the same asdefined above,

R^(III5) represents a saturated hydrocarbon group having 1 to 12 carbonatoms,

z2A1 represents an integer of 0 to 6, and

X^(I2) represents a divalent saturated hydrocarbon group having 1 to 11carbon atoms, —CH₂— included in the saturated hydrocarbon group may bereplaced by —O—, —S— or —CO—, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a halogen atom or ahydroxy group.

Examples of the saturated hydrocarbon group having 1 to 12 carbon atomsrepresented by R^(III5) include linear or branched alkyl groups such asa methyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a nonyl group, a decylgroup, an undecyl group and a dodecyl group.

Examples of the divalent saturated hydrocarbon group represented by X¹²include those which are the same as the divalent saturated hydrocarbongroup represented by X^(III3).

The structural unit represented by formula (II-2-A-1) is more preferablya structural unit represented by formula (II-2-A-2):

wherein, in formula (II-2-A-2),

R^(III3), R^(III5) and ZA⁺ are the same as defined above, and

m and nA each independently represent 1 or 2.

The structural unit represented by formula (II-2-A′) includes, forexample, the following structural units, structural units in which agroup corresponding to a methyl group of R^(III3) is substituted with analkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, ahalogen atom (e.g., fluorine atom) or a halogen atom (e.g.,trifluoromethyl group, etc.) and the structural units mentioned in WO2012/050015 A. ZA⁺ represents an organic cation.

The structural unit having a sulfonio group and an organic anion in aside chain is preferably a structural unit represented by formula(II-1-1):

wherein, in formula (II-1-1),

A^(II1) represents a single bond or a divalent linking group,

R^(II1) represents a divalent aromatic hydrocarbon group having 6 to 18carbon atoms,

R^(II2) and R^(II3) each independently represent a hydrocarbon grouphaving 1 to 18 carbon atoms, and R^(II2) and R^(II3) may be bonded toeach other to form a ring together with sulfur atoms to which R^(II2)and R^(II3) are bonded,

R^(II4) represents a hydrogen atom, a halogen atom, or an alkyl grouphaving 1 to 6 carbon atoms which may have a halogen atom, and

A⁻ represents an organic anion.

Examples of the divalent aromatic hydrocarbon group having 6 to 18carbon atoms represented by R^(II1) include a phenylene group and anaphthylene group.

Examples of the hydrocarbon group represented by R^(II2) and R^(II3)include an alkyl group, an alicyclic hydrocarbon group, an aromatichydrocarbon group, and groups obtained by combining these groups.

Examples of the halogen atom represented by R^(II4) include a fluorineatom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have ahalogen atom represented by R^(II4) include those which are the same asthe alkyl group having 1 to 6 carbon atoms which may have a halogen atomrepresented by R^(a8).

Examples of the divalent linking group represented by A^(II1) include adivalent saturated hydrocarbon group having 1 to 18 carbon atoms, and—CH₂— included in the divalent saturated hydrocarbon group may bereplaced by —O—, —S— or —CO—. Specific examples thereof include thosewhich are the same as the divalent saturated hydrocarbon group having 1to 18 carbon atoms represented by X^(III3).

Examples of the structural unit including a cation in formula (II-1-1)include the following structural units and structural units in which agroup corresponding to a methyl group of R^(II4) is substituted with ahydrogen atom, a fluorine atom, a trifluoromethyl group and the like.

Examples of the organic anion represented by A-include a sulfonic acidanion, a sulfonylimide anion, a sulfonylmethide anion and a carboxylicacid anion. The organic anion represented by A⁻ is preferably a sulfonicacid anion, and the sulfonic acid anion is more preferably an anionincluded in the below-mentioned salt represented by formula (B1).

Examples of the sulfonylimide anion include the followings.

Examples of the sulfonylmethide anion include the followings.

Examples of the carboxylic acid anion include the followings.

Examples of the structural unit represented by formula (II-1-1) includestructural units shown below.

When the structural unit (II) is included in the resin (A), the contentof the structural unit (II) is preferably 1 to 20 mol %, more preferably2 to 15 mol %, and still more preferably 3 to 10 mol %, based on allstructural units of the resin (A).

The resin (A) may include structural units other than the structuralunits mentioned above, and examples of such structural unit includestructural units well-known in the art.

The resin (A) is preferably a resin including a structural unit (a1).Particularly, the resin (Ap) is more preferably a resin composed of astructural unit (IP), a structural unit (a1) and a structural unit (s),that is, a copolymer of a salt (I), a monomer (a1) and a monomer (s).The resin (A) including no structural unit (IP) is preferably a resincomposed of a structural unit (a1) and a structural unit (s).

The structural unit (a1) is preferably at least one selected from thegroup consisting of a structural unit (a1-0), a structural unit (a1-1)and a structural unit (a1-2) (preferably the structural unit having acyclohexyl group and a cyclopentyl group), more preferably at least two,and still more preferably at least two selected from the groupconsisting of a structural unit (a1-1) and a structural unit (a1-2).

The structural unit (s) is preferably at least one selected from thegroup consisting of a structural unit (a2) and a structural unit (a3).The structural unit (a2) is preferably a structural unit (a2-1) or astructural unit (a2-A). The structural unit (a3) is preferably at leastone selected from the group consisting of a structural unit representedby formula (a3-1), a structural unit represented by formula (a3-2) and astructural unit represented by formula (a3-4).

The respective structural units constituting the resin (A) may be usedalone, or two or more structural units may be used in combination. Usinga monomer from which these structural units are derived, it is possibleto produce by a known polymerization method (e.g. radical polymerizationmethod). The content of the respective structural units included in theresin (A) can be adjusted according to the amount of the monomer used inthe polymerization.

The weight-average molecular weight of the resin (A) is preferably 2,000or more (more preferably 2,500 or more, and still more preferably 3,000or more), and 50,000 or less (more preferably 30,000 or less, and stillmore preferably 15,000 or less). In the present specification, theweight-average molecular weight is a value determined by gel permeationchromatography under the conditions mentioned in Examples. Thestructural unit (IP) may constitute a dimer, a trimer, and a compoundhaving a weight-average molecular weight of less than 2,000.

[Carboxylic Acid Generator]

The carboxylic acid generator of the present disclosure is a carboxylicacid generator including a carboxylate (I) or a structural unit (IP).The structural unit (IP) can be included as a compound or a resinobtained by polymerizing a plurality thereof. The carboxylate (I) orstructural unit (IP) of the present disclosure can act as a carboxylicacid generator in the resist composition. When using the carboxylate (I)as the carboxylic acid generator in the resist composition, thecarboxylic acid generator may include the carboxylate (I) alone, or twoor more thereof. When using the structural unit (IP) as the carboxylicacid generator in the resist composition, the compound or resinincluding the structural unit (IP) may be used alone or in combinationof two or more thereof. The carboxylic acid generator of the presentdisclosure may include both the carboxylate (I) and structural unit(IP).

As mentioned later, the carboxylic acid generator of the presentdisclosure may further include an acid generator known in the resistfield other than the carboxylate (I) (hereinafter sometimes referred toas “acid generator (B)”) and/or a carboxylate known in the resist fieldother than the carboxylate (I). The acid generator (B) may be usedalone, or in combination of two or more thereof.

When the carboxylic acid generator includes the acid generator (B), aratio of the content of the carboxylate (I) to that of the acidgenerator (B) (mass ratio; carboxylate (I):acid generator (B)) isusually 1:99 to 100:0, preferably 1:99 to 99:1, more preferably 2:98 to98:2, still more preferably 5:95 to 95:5, yet more preferably 15:85 to85:15, and particularly preferably 10:90 to 40:60.

[Resist Composition]

The resist composition of the present disclosure includes the carboxylicacid generator of the present disclosure. The carboxylic acid generatorhere may be a resin (Ap) including a structural unit (IP). That is, theresist composition of the present disclosure may include an acidgenerator including at least one of a structural unit (IP) and acarboxylate (I), or including a structural unit (IP) and a carboxylate(I). The structural unit (IP) may be in a form of either compound orresin. In other words, the resist composition of the present disclosuremay include, as the carboxylic acid generator, a resin and/or a resin(Ap), and a carboxylate (I). The resist composition of the presentdisclosure preferably include a resin including a structural unit (a1)having an acid-labile group. That is, the resist composition morepreferably includes (a) a carboxylate (I) and a resin (A),

(b) a resin (Ap) including a structural unit (IP) and a structural unit(a1) having an acid-labile group, or

(c) a resin (Ap) including a structural unit (IP) and a resin (A). Ofthese, the resist composition is preferably the resist composition (b).Two or more resins (A) and/or resins (Ap) may be included.

It is preferable that the resist composition of the present disclosurefurther includes an acid generator known in the resist field(hereinafter sometimes referred to as “acid generator (B)”, a quencher(hereinafter sometimes referred to as “quencher (C)”) and/or a solvent(hereinafter sometimes referred to as “solvent (E)”).

<Carboxylic Acid Generator>

The content of the carboxylate (I) of the present disclosure ispreferably about 0.01 to 15% by mass, more preferably about 0.001 to 10%by mass, still more preferably about 0.001 to 8% by mass, and yet morepreferably about 0.005 to 7% by mass, based on the solid content of theresist composition.

The content of the resin (Ap) of the present disclosure is preferably80% by mass or more 99% by mass or less, and more preferably 90% by massor more 99% by mass or less, based on the solid content of the resistcomposition.

<Resin Other than Resin (A)>

The resist composition of the present disclosure may use a resin (Ap) incombination with a resin other than the resin (A). Examples of the resin(Ap) and the resin other than the resin (A) include a resin (AX)including the same structural unit as that of the resin (A), except thatno structural unit (a1) is included in the above-mentioned resin (A), aresin including a structural unit (a4) and/or a structural unit (a5)(including neither structural unit (IP) nor structural unit (a1),hereinafter sometimes referred to as “resin (X)”) and the like.

Examples of the resin (AX) include a resin including a structural unit(a2), and a resin including a structural unit (a2-A) is preferable. Inthe resin (AX), the content of the structural unit (a2-A) is preferably5 mol % or more, more preferably 10 mol % or more, and still morepreferably 15 mol % or more, and is preferably 80 mol % or less, andmore preferably 70 mol % or less, based on the total of all structuralunits of the resin (AX).

Examples of the structural unit, which may be further included in theresin (X), include a structural unit (a2), a structural unit (a3) andstructural units derived from other known monomers. Particularly, theresin (X) is preferably a resin composed only of a structural unit (a4)and/or a structural unit (a5), and more preferably a resin composed onlyof a structural unit (a4).

When the resin (X) includes a structural unit (a4), the content of thestructural unit (a4) is 20 mol % or more, preferably 30 mol % or more,more preferably 40 mol % or more, and still more preferably 45 mol % ormore, based on the total of all structural units of the resin (X). Thecontent is also 100 mol % or less, preferably 80 mol % or less, morepreferably 70 mol % or less, still more preferably 60 mol % or less, andyet more preferably 55 mol % or less. Specifically, the content is 20 to100 mol %, preferably 20 to 80 mol %, more preferably 30 to 70 mol %,still more preferably 40 to 60 mol %, and yet more preferably 45 to 55mol %. When the resin (X) includes a structural unit (a5), the contentof the structural unit (a5) is 20 mol % or more, preferably 30 mol % ormore, more preferably 40 mol % or more, and still more preferably 45 mol% or more, based on the total of all structural units of the resin (X).The content is also 100 mol % or less, preferably 80 mol % or less, morepreferably 70 mol % or less, still more preferably 60 mol % or less, andyet more preferably 55 mol % or less. Specifically, the content is 20 to100 mol %, preferably 20 to 80 mol %, more preferably 30 to 70 mol %,still more preferably 40 to 60 mol %, and yet more preferably 45 to 55mol %. When the resin (X) includes a structural unit (a4) and astructural unit (a5), the total content of the structural unit (a4) andthe structural unit (a5) is 40 mol % or more, preferably 60 mol % ormore, more preferably 70 mol % or more, and still more preferably 80 mol% or more, based on the total of all structural units of the resin (X).The content is also 100 mol % or less. Specifically, the content is 40to 100 mol %, preferably 60 to 100 mol %, more preferably 70 to 100 mol%, and still more preferably 80 to 100 mol %.

The respective structural unit constituting the resin (AX) and the resin(X) may be used alone, or two or more structural units may be used incombination. Using a monomer from which these structural units arederived, it is possible to produce by a known polymerization method(e.g. radical polymerization method). The content of the respectivestructural units included in the resin (AX) and the resin (X) can beadjusted according to the amount of the monomer used in thepolymerization.

The weight-average molecular weight of the resin (AX) and the resin (X)is preferably 6,000 or more (more preferably 7,000 or more) and 80,000or less (more preferably 60,000 or less). The measurement means of theweight-average molecular weight of the resin (AX) and the resin (X) isthe same as in the case of the resin (A).

When the resist composition of the present disclosure includes the resin(X), the content is preferably 1 to 60 parts by mass, more preferably 1to 50 parts by mass, still more preferably 1 to 40 parts by mass, yetmore preferably 1 to 30 parts by mass, and further preferably 1 to 8parts by mass, based on 100 parts by mass of the resin (A).

The content of the resin (A) or like in the resist composition ispreferably 80% by mass or more and 99% by mass or less, and morepreferably 90% by mass or more and 99% by mass or less, based on thesolid component of the resist composition. When including resins otherthan the resin (A), the total content of the resin (A) or like andresins other than the resin (A) is preferably 80% by mass or more and99% by mass or less, and more preferably 90% by mass or more and 99% bymass or less, based on the solid component of the resist composition.The solid component of the resist composition and the content of theresin thereto can be measured by a known analysis means such as liquidchromatography or gas chromatography.

<Acid Generator>

Either nonionic or ionic acid generator may be used as the acidgenerator (B). Examples of the nonionic acid generator include sulfonateesters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate,N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate),sulfones (e.g., disulfone, ketosulfone, sulfonyldiazomethane) and thelike. Typical examples of the ionic acid generator include onium saltscontaining an onium cation (e.g., diazonium salt, phosphonium salt,sulfonium salt, iodonium salt). Examples of the anion of the onium saltinclude sulfonic acid anion, sulfonylimide anion, sulfonylmethide anionand the like.

Specific examples of the acid generator (B) include compounds generatingan acid upon exposure to radiation mentioned in JP 63-26653 A, JP55-164824 A, JP 62-69263 A, JP 63-146038 A, JP 63-163452 A, JP 62-153853A, JP 63-146029 A, U.S. Pat. Nos. 3,779,778, 3,849,137, DE Patent No.3914407 and EP Patent No. 126,712. Compounds produced by a known methodmay also be used. Two or more acid generators (B) may also be used incombination.

The acid generator (B) is preferably a salt represented by formula (B1)(hereinafter sometimes referred to as “acid generator (B1)”):

wherein, in formula (B1),

Q^(b1) and Q^(b2) each independently represent a hydrogen atom, afluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms or analkyl group having 1 to 6 carbon atoms.

L^(b1) represents a divalent saturated hydrocarbon group having 1 to 24carbon atoms, —CH₂— included in the divalent saturated hydrocarbon groupmay be replaced by —O— or —CO—, and a hydrogen atom included in thedivalent saturated hydrocarbon group may be substituted with a fluorineatom or a hydroxy group,

Y represents a methyl group which may have a substituent or an alicyclichydrocarbon group having 3 to 24 carbon atoms which may have asubstituent, and —CH₂— included in the alicyclic hydrocarbon group maybe replaced by —O—, —S—, —SO₂— or —CO—, and

Z1⁺ represents an organic cation.

Examples of the perfluoroalkyl group represented by Q^(b1) and Q^(b2)include a trifluoromethyl group, a perfluoroethyl group, aperfluoropropyl group, a perfluoroisopropyl group, a perfluorobutylgroup, a perfluorosec-butyl group, a perfluorotert-butyl group, aperfluoropentyl group and a perfluorohexyl group.

Examples of the alkyl group represented by Q^(b1) and Q^(b2) include amethyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group and the like.

The acid generator (B) is preferably a fluorine-containing acidgenerator. Preferably either Q^(b1) or Q^(b2) is a fluorine atom or aperfluoroalkyl group, more preferably both Q^(b1) or Q^(b2) are fluorineatoms or trifluoromethyl groups, and still more preferably both arefluorine atoms.

Examples of the divalent saturated hydrocarbon group in L^(b1) include alinear alkanediyl group, a branched alkanediyl group, and a monocyclicor polycyclic divalent alicyclic saturated hydrocarbon group, or thedivalent saturated hydrocarbon group may be a group formed by combiningtwo or more of these groups.

Specific examples thereof include linear alkanediyl groups such as amethylene group, an ethylene group, a propane-1,3-diyl group, abutane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diylgroup, a heptane-1,7-diyl group, an octane-1,8-diyl group, anonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diylgroup, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, atetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, ahexadecane-1,16-diyl group and a heptadecane-1,17-diyl group;

branched alkanediyl groups such as an ethane-1,1-diyl group, apropane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diylgroup, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group and a2-methylbutane-1,4-diyl group;

monocyclic divalent alicyclic saturated hydrocarbon groups which arecycloalkanediyl groups such as a cyclobutane-1,3-diyl group, acyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group and acyclooctane-1,5-diyl group; and

polycyclic divalent alicyclic saturated hydrocarbon groups such as anorbornane-1,4-diyl group, a norbornane-2,5-diyl group, anadamantane-1,5-diyl group and an adamantane-2,6-diyl group.

The group in which —CH₂— included in the divalent saturated hydrocarbongroup represented by L^(b1) is replaced by —O— or —CO— includes, forexample, a group represented by any one of formula (b1-1) to formula(b1-3). In groups represented by formula (b1-1) to formula (b1-3) andgroups represented by formula (b1-4) to formula (b1-11) which arespecific examples thereof, * and ** represent a bonding site, and *represents a bond to —Y.

In formula (b1-1),

L^(b2) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 22 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom,

L^(b3) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 22 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group, and —CH₂— included in the saturated hydrocarbon group maybe replaced by —O— or —CO—, and

the total number of carbon atoms of L^(b2) and L^(b3) is 22 or less.

In formula (b1-2),

L^(b4) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 22 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom,

L^(b5) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 22 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group, and —CH₂— included in the saturated hydrocarbon group maybe replaced by —O— or —CO—, and

the total number of carbon atoms of L^(b4) and L^(b3) is 22 or less.

In formula (b1-3),

L^(b6) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 23 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group,

L^(b7) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 23 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group, and —CH₂— included in the saturated hydrocarbon group maybe replaced by —O— or —CO—,

in which the total number of carbon atoms of L^(b6) and L^(b7) is 23 orless.

In groups represented by formula (b1-1) to formula (b1-3), when —CH₂—included in the saturated hydrocarbon group is replaced by —O— or —CO—,the number of carbon atoms before replacement is taken as the number ofcarbon atoms of the saturated hydrocarbon group.

Examples of the divalent saturated hydrocarbon group include those whichare the same as the divalent saturated hydrocarbon group of L^(b1).

L^(b2) is preferably a single bond, a methylene group, —CH(CF₃)—,—C(CF₃)₂—.

L^(b3) is preferably a divalent saturated hydrocarbon group having 1 to4 carbon atoms.

L^(b4) is preferably a divalent saturated hydrocarbon group having 1 to8 carbon atoms, and a hydrogen atom included in the divalent saturatedhydrocarbon group may be substituted with a fluorine atom.

L^(b5) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 8 carbon atoms.

L^(b6) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 4 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom.

L^(b7) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 18 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group, and —CH₂— included in the divalent saturated hydrocarbongroup may be replaced by —O— or —CO—.

The group in which —CH₂— included in the divalent saturated hydrocarbongroup represented by L^(b1) is replaced by —O— or —CO— is preferably agroup represented by formula (b1-1) or formula (b1-3).

Examples of the group represented by formula (b1-1) include groupsrepresented by formula (b1-4) to formula (b1-8).

In formula (b1-4),

L^(b8) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 22 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group.

In formula (b1-5),

L^(b9) represents a divalent saturated hydrocarbon group having 1 to 20carbon atoms, and-CH₂— included in the divalent saturated hydrocarbongroup may be replaced by —O— or —CO—.

L^(b10) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 19 carbon atoms, and a hydrogen atom included in thedivalent saturated hydrocarbon group may be substituted with a fluorineatom or a hydroxy group, and

the total number of carbon atoms of L^(b9) and L^(b10) is 20 or less.

In formula (b1-6),

L^(b11) represents a divalent saturated hydrocarbon group having 1 to 21carbon atoms,

L^(b12) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 20 carbon atoms, and a hydrogen atom included in thedivalent saturated hydrocarbon group may be substituted with a fluorineatom or a hydroxy group, and

the total number of carbon atoms of L^(b11) and L^(b12) is 21 or less.

In formula (b1-7),

L^(b13) represents a divalent saturated hydrocarbon group having 1 to 19carbon atoms,

L^(b14) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 18 carbon atoms, and —CH₂— included in the divalentsaturated hydrocarbon group may be replaced by —O— or —CO—,

L^(b15) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 18 carbon atoms, and a hydrogen atom included in thedivalent saturated hydrocarbon group may be substituted with a fluorineatom or a hydroxy group, and

the total number of carbon atoms of L^(b13) to L^(b15) is 19 or less.

In formula (b1-8),

L^(b16) represents a divalent saturated hydrocarbon group having 1 to 18carbon atoms, and —CH₂— included in the divalent saturated hydrocarbongroup may be replaced by —O— or —CO—,

L^(b17) represents a divalent saturated hydrocarbon group having 1 to 18carbon atoms,

L^(b18) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 17 carbon atoms, and a hydrogen atom included in thedivalent saturated hydrocarbon group may be substituted with a fluorineatom or a hydroxy group, and

in which the total number of carbon atoms of L^(b16) to L^(b18) is 19 orless.

L^(b8) is preferably a divalent saturated hydrocarbon group having 1 to4 carbon atoms.

L^(b9) is preferably a divalent saturated hydrocarbon group having 1 to8 carbon atoms.

L^(b10) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 19 carbon atoms, and more preferably a single bond ora divalent saturated hydrocarbon group having 1 to 8 carbon atoms.

L^(b11) is preferably a divalent saturated hydrocarbon group having 1 to8 carbon atoms.

L^(b12) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 8 carbon atoms.

L^(b13) is preferably a divalent saturated hydrocarbon group having 1 to12 carbon atoms.

L^(b14) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 6 carbon atoms.

L^(b15) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 18 carbon atoms, and more preferably a single bond ora divalent saturated hydrocarbon group having 1 to 8 carbon atoms.

L^(b16) is preferably a divalent saturated hydrocarbon group having 1 to12 carbon atoms.

L^(b17) is preferably a divalent saturated hydrocarbon group having 1 to6 carbon atoms.

L^(b18) is preferably a single bond or a divalent saturated hydrocarbongroup having 1 to 17 carbon atoms, and more preferably a single bond ora divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of the group represented by formula (b1-3) include groupsrepresented by formula (b1-9) to formula (b1-11).

In formula (b1-9),

L^(b19) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 23 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom,

L^(b20) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 23 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom, ahydroxy group or an alkylcarbonyloxy group, —CH₂— included in thealkylcarbonyloxy group may be replaced by —O— or —CO—, and a hydrogenatom included in the alkylcarbonyloxy group may be substituted with ahydroxy group, and the total number of carbon atoms of L^(b19) andL^(b20) is 23 or less.

In formula (b1-10),

L^(b21) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 21 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom,

L^(b22) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 21 carbon atoms,

L^(b23) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 21 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom, ahydroxy group or an alkylcarbonyloxy group, —CH₂— included in thealkylcarbonyloxy group may be replaced by —O— or —CO—, and a hydrogenatom included in the alkylcarbonyloxy group may be substituted with ahydroxy group, and

the total number of carbon atoms of L^(b21), L^(b22) and L^(b23) is 21or less.

In formula (b1-11),

L^(b24) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 20 carbon atoms, and a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom,

L^(b25) represents a divalent saturated hydrocarbon group having 1 to 21carbon atoms,

L^(b26) represents a single bond or a divalent saturated hydrocarbongroup having 1 to 20 carbon atoms, a hydrogen atom included in thesaturated hydrocarbon group may be substituted with a fluorine atom, ahydroxy group or an alkylcarbonyloxy group, —CH₂— included in thealkylcarbonyloxy group may be replaced by —O— or —CO—, and a hydrogenatom included in the alkylcarbonyloxy group may be substituted with ahydroxy group,

the total number of carbon atoms of L^(b24), L^(b25) and L^(b26) is 21or less.

In groups represented by formula (b1-9) to formula (b1-11), when ahydrogen atom included in the saturated hydrocarbon group is substitutedwith an alkylcarbonyloxy group, the number of carbon atoms beforesubstitution is taken as the number of carbon atoms of the saturatedhydrocarbon group.

Examples of the alkylcarbonyloxy group include an acetyloxy group, apropionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group,an adamantylcarbonyloxy group and the like.

Examples of the group represented by formula (b1-4) include thefollowings.

Examples of the group represented by formula (b1-5) include thefollowings.

Examples of the group represented by formula (b1-6) include thefollowings.

Examples of the group represented by formula (b1-7) include thefollowings.

Examples of the group represented by formula (b1-8) include thefollowings.

Examples of the group represented by formula (b1-2) include thefollowings.

Examples of the group represented by formula (b1-9) include thefollowings.

Examples of the group represented by formula (b1-10) include thefollowings.

Examples of the group represented by formula (b1-11) include thefollowings.

Examples of the alicyclic hydrocarbon group represented by Y includegroups represented by formula (Y1) to formula (Y11) and formula (Y36) toformula (Y38).

When —CH₂— included in the alicyclic hydrocarbon group represented by Yis replaced by O—, —S—, —SO₂— or —CO—, the number may be 1, or 2 ormore. Examples of such group include groups represented by formula (Y12)to formula (Y35) and formula (Y39) to formula (Y43). The bonding site of—O— or —CO— of groups shown below may be replaced by —S— or —SO₂—.

The alicyclic hydrocarbon group represented by Y is preferably a grouprepresented by any one of formula (Y1) to formula (Y20), formula (Y26),formula (Y27), formula (Y30), formula (Y31) and formula (Y39) to formula(Y43), more preferably a group represented by formula (Y11), formula(Y15), formula (Y16), formula (Y20), formula (Y26), formula (Y27),formula (Y30), formula (Y31), formula (Y39), formula (Y40), formula(Y42) or formula (Y43), and still more preferably a group represented byformula (Y11), formula (Y15), formula (Y20), formula (Y26), formula(Y27), formula (Y30), formula (Y31), formula (Y39), formula (Y40),formula (Y42) or formula (Y43).

When the alicyclic hydrocarbon group represented by Y is a spiro ringcontaining an oxygen atom, such as formula (Y28) to formula (Y35),formula (Y39) to formula (Y40), formula (Y42), formula (Y43), etc., thealkanediyl group between two oxygen atoms preferably has one or morefluorine atoms. Of alkanediyl groups included in a ketal structure, itis preferable that a methylene group adjacent to the oxygen atom is notsubstituted with a fluorine atom.

Examples of the substituent of the methyl group represented by Y includea halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbonatoms, a glycidyloxy group, a —(CH₂)_(ja)—CO—O—R^(b1) group or a—(CH₂)_(ja)—O—CO—R^(b1) group (wherein R^(b1) represents an alkyl grouphaving 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbonatoms, or a group obtained by combining these groups, —CH₂— included inthe alkyl group and the alicyclic hydrocarbon group may be replaced by—O—, —SO₂— or —CO—, a hydrogen atom included in the alkyl group, thealicyclic hydrocarbon group and the aromatic hydrocarbon group may besubstituted with a hydroxy group or a fluorine atom, and ja representsan integer of 0 to 4).

Examples of the substituent of the alicyclic hydrocarbon grouprepresented by Y include a halogen atom, a hydroxy group, an alkyl grouphaving 1 to 16 carbon atoms which may be substituted with a hydroxygroup (—CH₂— included in the alkyl group may be replaced by —O— or—CO—), an alicyclic hydrocarbon group having 3 to 16 carbon atoms, anaromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl grouphaving 7 to 21 carbon atoms, a glycidyloxy group, a—(CH₂)_(ja)—CO—O—R^(b1) group or a —(CH₂)_(ja)—O—CO—R^(b1) group(wherein R^(b1) represents an alkyl group having 1 to 16 carbon atoms,an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatichydrocarbon group having 6 to 18 carbon atoms, or a group obtained bycombining these groups, —CH₂— included in the alkyl group and thealicyclic hydrocarbon group may be replaced by —O—, —SO₂— or —CO—, ahydrogen atom included in the alkyl group, the alicyclic hydrocarbongroup and the aromatic hydrocarbon group may be substituted with ahydroxy group or a fluorine atom, and ja represents an integer of 0 to4).

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

Examples of the alicyclic hydrocarbon group include a cyclopentyl group,a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexylgroup, a cycloheptyl group, a cyclooctyl group, a norbornyl group, anadamantyl group and the like. The alicyclic hydrocarbon group may have achain hydrocarbon group, and examples thereof include a methylcyclohexylgroup, a dimethylcyclohexyl group and the like. The number of carbonatoms of the alicyclic hydrocarbon group is preferably 3 to 12, and morepreferably 3 to 10.

Examples of the aromatic hydrocarbon group include aryl groups such as aphenyl group, a naphthyl group, an anthryl group, a biphenyl group and aphenanthryl group. The aromatic hydrocarbon group may have a chainhydrocarbon group or an alicyclic hydrocarbon group, and an aromatichydrocarbon group which has a chain hydrocarbon group having 1 to 18carbon atoms (a tolyl group, a xylyl group, a cumenyl group, a mesitylgroup, a p-methylphenyl group, a p-ethylphenyl group, ap-tert-butylphenyl group, a 2,6-diethylphenyl group, a2-methyl-6-ethylphenyl group, etc.), and an aromatic hydrocarbon groupwhich has an alicyclic hydrocarbon group having 3 to 18 carbon atoms (ap-adamantylphenyl group, a p-cyclohexylphenyl group, etc.) arepreferable. The number of carbon atoms of the aromatic hydrocarbon groupis preferably 6 to 14, and more preferably 6 to 10.

Examples of the alkyl group include a methyl group, an ethyl group, apropyl group, an isopropyl group, a butyl group, a sec-butyl group, atert-butyl group, a pentyl group, a hexyl group, a heptyl group, a2-ethylhexyl group, an octyl group, a nonyl group, a decyl group, anundecyl group, a dodecyl group and the like. The number of carbon atomsof the alkyl group is preferably 1 to 12, more preferably 1 to 6, andstill more preferably 1 to 4.

Examples of the alkyl group substituted with a hydroxy group includehydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethylgroup.

Examples of the aralkyl group include a benzyl group, a phenethyl group,a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.

Examples of the group in which —CH₂— included in the alkyl group isreplaced by —O—, —SO₂— or —CO— include an alkoxy group, an alkylsulfonylgroup, an alkoxycarbonyl group, an alkylcarbonyl group, analkylcarbonyloxy group, or a group obtained by combining these groups.

Examples of the alkoxy group include a methoxy group, an ethoxy group, apropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, aheptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxygroup. The number of carbon atoms of the alkoxy group is preferably 1 to12, more preferably 1 to 6, and still more preferably 1 to 4.

Examples of the alkylsulfonyl group include a methylsulfonyl group, anethylsulfonyl group, a propylsulfonyl group and the like. The number ofcarbon atoms of the sulfonyl group is preferably 1 to 12, morepreferably 1 to 6, and still more preferably 1 to 4.

Examples of the alkoxycarbonyl group include a methoxycarbonyl group, anethoxycarbonyl group, a butoxycarbonyl group and the like. The number ofcarbon atoms of the alkoxycarbonyl group is preferably 2 to 12, morepreferably 2 to 6, and still more preferably 2 to 4.

Examples of the alkylcarbonyl group include an acetyl group, a propionylgroup and a butyryl group. The number of carbon atoms of thealkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, andstill more preferably 2 to 4.

Examples of the alkylcarbonyloxy group include an acetyloxy group, apropionyloxy group, a butyryloxy group and the like. The number ofcarbon atoms of the alkylcarbonyloxy group is preferably 2 to 12, morepreferably 2 to 6, and still more preferably 2 to 4.

Examples of the combined group include a group obtained by combining analkoxy group with an alkyl group, a group obtained by combining analkoxy group with an alkoxy group, a group obtained by combining analkoxy group with an alkylcarbonyl group, a group obtained by combiningan alkoxy group with an alkylcarbonyloxy group and the like.

Examples of the group obtained by combining an alkoxy group with analkyl group include alkoxyalkyl groups such as a methoxymethyl group, amethoxyethyl group, an ethoxyethyl group and an ethoxymethyl group. Thenumber of carbon atoms of the alkoxyalkyl group is preferably 2 to 12,more preferably 2 to 6, and still more preferably 2 to 4.

Examples of the group obtained by combining an alkoxy group with analkoxy group include alkoxyalkoxy groups such as a methoxymethoxy group,a methoxyethoxy group, an ethoxymethoxy group and an ethoxyethoxy group.The number of carbon atoms of the alkoxyalkoxy group is preferably 2 to12, more preferably 2 to 6, and still more preferably 2 to 4.

Examples of the group obtained by combining an alkoxy group with analkylcarbonyl group include alkoxyalkylcarbonyl groups such as amethoxyacetyl group, a methoxypropionyl group, an ethoxyacetyl group andan ethoxypropionyl group. The number of carbon atoms of thealkoxyalkylcarbonyl group is preferably 3 to 13, more preferably 3 to 7,and still more preferably 3 to 5.

Examples of the group obtained by combining an alkoxy group with analkylcarbonyloxy group include alkoxyalkylcarbonyloxy groups such as amethoxyacetyloxy group, a methoxypropionyloxy group, an ethoxyacetyloxygroup and an ethoxypropionyloxy group. The number of carbon atoms of thealkoxyalkylcarbonyloxy group is preferably 3 to 13, more preferably 3 to7, and still more preferably 3 to 5.

Examples of the group in which —CH₂— included in the alicyclichydrocarbon group is replaced by —O—, —SO₂— or —CO— include groupsrepresented by formula (Y12) to formula (Y35) and formula (Y39) toformula (Y43).

Y is preferably an alicyclic hydrocarbon group having 3 to 24 carbonatoms which may have a substituent, more preferably an alicyclichydrocarbon group having 3 to 20 carbon atoms which may have asubstituent, still more preferably an alicyclic hydrocarbon group having3 to 18 carbon atoms which may have a substituent, and yet morepreferably an adamantyl group which may have a substituent, or anorbornyl group, and —CH₂— constituting the alicyclic hydrocarbon group,the adamantyl group or the norbornyl group may be replaced by —CO—,—SO₂— or —CO—. Specifically, the followings are exemplified.

Of these, Y is preferably an adamantyl group, a hydroxyadamantyl group,an oxoadamantyl group, a norbornanelactone group, or groups representedby formula (Y42), formula (Y100) to formula (Y114) and formula (Y134) toformula (Y139).

The anion in the salt represented by formula (B1) is preferably anionsrepresented by formula (B1-A-1) to formula (B1-A-65) [hereinaftersometimes referred to as “anion (B1-A-1)” according to the number offormula], and more preferably anion represented by any one of formula(B1-A-1) to formula (B1-A-4), formula (B1-A-9), formula (B1-A-10),formula (B1-A-24) to formula (B1-A-33), formula (B1-A-36) to formula(B1-A-40) and formula (B1-A-47) to formula (B1-A-65).

R^(i2) to R^(i7) each independently represent, for example, an alkylgroup having 1 or 4 carbon atoms, and preferably a methyl group or anethyl group. R^(i8) is, for example, a chain hydrocarbon group having 1to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbonatoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or agroup formed by combining these groups, and more preferably a methylgroup, an ethyl group, a cyclohexyl group or an adamantyl group. L^(A4)1is a single bond or an alkanediyl group having 1 to 4 carbon atoms.Q^(b1) and Q^(b2) are the same as defined above.

Specific examples of the anion in the salt represented by formula (B1)include anions mentioned in JP 2010-204646 A.

The anion in the salt represented by formula (B1) preferably includesanions represented by formula (B1a-1) to formula (B1a-43).

Of these, anion represented by any one of formula (B1a-1) to formula(B1a-3), formula (B1a-7) to formula (B1a-16), formula (B1a-18), formula(B1a-19) and formula (B1a-22) to formula (B1a-38) is preferable.

Examples of the sulfonylimide anion include the followings.

Examples of the sulfonylmethide anion include the followings.

Examples of the organic cation of Z⁺ include an organic onium cation, anorganic sulfonium cation, an organic iodonium cation, an organicammonium cation, a benzothiazolium cation and an organic phosphoniumcation. Of these, an organic sulfonium cation and an organic iodoniumcation are preferable, and an aryl sulfonium cation is more preferable.Specific examples thereof include a cation represented by any one offormula (b2-1) to formula (b2-4) (hereinafter sometimes referred to as“cation (b2-1)” according to the number of formula).

In formula (b2-1) to formula (b2-4),

R^(b4) to R^(b6) each independently represent a chain hydrocarbon grouphaving 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to36 carbon atoms or an aromatic hydrocarbon group having 6 to 36 carbonatoms, a hydrogen atom included in the chain hydrocarbon group may besubstituted with a hydroxy group, an alkoxy group having 1 to 12 carbonatoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms or anaromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atomincluded in the alicyclic hydrocarbon group may be substituted with ahalogen atom, an aliphatic hydrocarbon group having 1 to 18 carbonatoms, an alkylcarbonyl group having 2 to 4 carbon atoms or aglycidyloxy group, and a hydrogen atom included in the aromatichydrocarbon group may be substituted with a halogen atom, a hydroxygroup, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, analkyl fluoride group having 1 to 12 carbon atoms or an alkoxy grouphaving 1 to 12 carbon atoms.

R^(b4) and R^(b5) may be bonded to each other to form a ring togetherwith sulfur atoms to which R^(b4) and R^(b5) are bonded, and —CH₂—included in the ring may be replaced by —O—, —S— or —CO—,

R^(b7) and R^(b8) each independently represent a halogen atom, a hydroxygroup, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or analkoxy group having 1 to 12 carbon atoms,

m2 and n2 each independently represent an integer of 0 to 5,

when m2 is 2 or more, a plurality of R^(b7) may be the same ordifferent, and when n2 is 2 or more, a plurality of R^(b8) may be thesame or different,

R^(b9) and R^(b10) each independently represent a chain hydrocarbongroup having 1 to 36 carbon atoms or an alicyclic hydrocarbon grouphaving 3 to 36 carbon atoms,

R^(b9) and R^(b10) may be bonded to each other to form a ring togetherwith sulfur atoms to which R^(b9) and R^(b10) are bonded, and —CH₂—included in the ring may be replaced by —O—, —S— or —CO—,

R^(b11) represents a hydrogen atom, a chain hydrocarbon group having 1to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbonatoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms,

R^(b12) represents a chain hydrocarbon group having 1 to 12 carbonatoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or anaromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atomincluded in the chain hydrocarbon group may be substituted with anaromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atomincluded in the aromatic hydrocarbon group may be substituted with analkoxy group having 1 to 12 carbon atoms or an alkylcarbonyloxy grouphaving 1 to 12 carbon atoms,

R^(b11) and R^(b12) may be bonded to each other to form a ring,including —CH—CO— to which R^(b11) and R^(b12) are bonded, and —CH₂—included in the ring may be replaced by —O—, —S— or —CO—,

R^(b13) to R^(b18) each independently represent a halogen atom, ahydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbonatoms, an alkyl fluoride group having 1 to 12 carbon atoms or an alkoxygroup having 1 to 12 carbon atoms,

L^(b31) represents a sulfur atom or an oxygen atom,

o2, p2, s2 and t2 each independently represent an integer of 0 to 5,

q2 and r2 each independently represent an integer of 0 to 4,

u2 represents 0 or 1, and

when o2 is 2 or more, a plurality of R^(b13) are the same or different,when p2 is 2 or more, a plurality of R^(b14) are the same or different,when q2 is 2 or more, a plurality of R^(b15) are the same or different,when r2 is 2 or more, a plurality of R^(b16) are the same or different,when s2 is 2 or more, a plurality of R^(b17) are the same or different,and when t2 is 2 or more, a plurality of R^(b18) are the same ordifferent.

The aliphatic hydrocarbon group represents a chain hydrocarbon group andan alicyclic hydrocarbon group.

Examples of the chain hydrocarbon group include alkyl groups such as amethyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group, an octyl group and a 2-ethylhexyl group.

Particularly, the chain hydrocarbon group of R^(b9) to R^(b12)preferably has 1 to 12 carbon atoms.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic,and examples of the monocyclic alicyclic hydrocarbon group includecycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctylgroup and a cyclodecyl group. Examples of the polycyclic alicyclichydrocarbon group include a decahydronaphthyl group, an adamantyl group,a norbornyl group and the following groups.

Particularly, the alicyclic hydrocarbon group of R^(b9) to R^(b12)preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbonatoms.

Examples of the alicyclic hydrocarbon group in which a hydrogen atom issubstituted with an aliphatic hydrocarbon group include amethylcyclohexyl group, a dimethylcyclohexyl group, a2-methyladamantan-2-yl group, a 2-ethyladamantan-2-yl group, a2-isopropyladamantan-2-yl group, a methylnorbornyl group, an isobornylgroup and the like. In the alicyclic hydrocarbon group in which ahydrogen atom is substituted with an aliphatic hydrocarbon group, thetotal number of carbon atoms of the alicyclic hydrocarbon group and thealiphatic hydrocarbon group is preferably 20 or less.

The alkyl fluoride group represents an alkyl group having 1 to 12 carbonatoms which has a fluorine atom, and examples thereof include afluoromethyl group, a difluoromethyl group, a trifluoromethyl group, aperfluorobutyl group and the like. The number of carbon atoms of thealkyl fluoride group is preferably 1 to 9, more preferably 1 to 6, stillmore preferably 1 to 4.

Examples of the aromatic hydrocarbon group include aryl groups such as aphenyl group, a biphenyl group, a naphthyl group and a phenanthrylgroup. The aromatic hydrocarbon group may have a chain hydrocarbon groupor an alicyclic hydrocarbon group, and examples thereof include anaromatic hydrocarbon group having a chain hydrocarbon group (a tolylgroup, a xylyl group, a cumenyl group, a mesityl group, a p-ethylphenylgroup, a p-tert-butylphenyl group, a 2,6-diethylphenyl group, a2-methyl-6-ethylphenyl group, etc.) and an aromatic hydrocarbon grouphaving an alicyclic hydrocarbon group (a p-cyclohexylphenyl group, ap-adamantylphenyl group, etc.). When the aromatic hydrocarbon group hasa chain hydrocarbon group or an alicyclic hydrocarbon group, a chainhydrocarbon group having 1 to 18 carbon atoms and an alicyclichydrocarbon group having 3 to 18 carbon atoms are preferable.

Examples of the aromatic hydrocarbon group in which a hydrogen atom issubstituted with an alkoxy group include a p-methoxyphenyl group and thelike.

Examples of the chain hydrocarbon group in which a hydrogen atom issubstituted with an aromatic hydrocarbon group include aralkyl groupssuch as a benzyl group, a phenethyl group, a phenylpropyl group, atrityl group, a naphthylmethyl group and a naphthylethyl group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, apropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, aheptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxygroup.

Examples of the alkylcarbonyl group include an acetyl group, a propionylgroup and a butyryl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

Examples of the alkylcarbonyloxy group include a methylcarbonyloxygroup, an ethylcarbonyloxy group, a propylcarbonyloxy group, anisopropylcarbonyloxy group, a butylcarbonyloxy group, asec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, apentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxygroup and a 2-ethylhexylcarbonyloxy group.

The ring formed by bonding R^(b4) and R^(b5) each other, together withsulfur atoms to which R^(b4) and R^(b5) are bonded, may be a monocyclic,polycyclic, aromatic, nonaromatic, saturated or unsaturated ring. Thisring includes a ring having 3 to 18 carbon atoms and is preferably aring having 4 to 18 carbon atoms. The ring containing a sulfur atomincludes a 3-membered to 12-membered ring and is preferably a 3-memberedto 7-membered ring and includes, for example, the following rings andthe like. * represents a bonding site.

The ring formed by combining R^(b9) and R^(b10) together may be amonocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturatedring. This ring includes a 3-membered to 12-membered ring and ispreferably a 3-membered to 7-membered ring. The ring includes, forexample, a thiolan-1-ium ring (tetrahydrothiophenium ring), athian-1-ium ring, a 1,4-oxathian-4-ium ring and the like.

The ring formed by combining R^(b11) and R^(b12) together may be amonocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturatedring. This ring includes a 3-membered to 12-membered ring and ispreferably a 3-membered to 7-membered ring. Examples thereof include anoxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, anoxoadamantane ring and the like.

Of cation (b2-1) to cation (b2-4), a cation (b2-1) is preferable.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

Examples of the cation (b2-4) include the following cations.

The acid generator (B) is a combination of the anion mentioned above andthe organic cation mentioned above, and these can be optionallycombined. The acid generator (B) preferably includes a combination ofanion represented by any one of formula (B1a-1) to formula (B1a-3),formula (B1a-7) to formula (B1a-16), formula (B1a-18), formula (B1a-19)and formula (B1a-22) to formula (B1a-38) with a cation (b2-1), a cation(b2-2), a cation (b2-3) or a cation (b2-4).

The acid generator (B) preferably includes those represented by formula(B1-1) to formula (B1-60), and of these acid generators, thosecontaining an arylsulfonium cation are preferable and those representedby formula (B1-1) to formula (B1-3), formula (B1-5) to formula (B1-7),formula (B1-11) to formula (B1-14), formula (B1-20) to formula (B1-26),formula (B1-29) and formula (B1-31) to formula (B1-60) are particularlypreferable.

In the resist composition of the present disclosure, the content of theacid generator is preferably 0.1% by mass or more and 99.9% by mass orless, more preferably 1% by mass or more and 45% by mass or less, stillmore preferably 1% by mass or more and 40% by mass or less, and yetpreferably 3% by mass or more and 40% by mass or less, based on thesolid content of the resist composition. When including the resin (A),the content of the acid generator is preferably 1 part by mass or moreand 45 parts by mass or less, more preferably 1 part by mass or more and40 parts by mass or less, and still more preferably 3 parts by mass ormore and 35 parts by mass or less, based on 100 parts by mass of theresin (A).

<Solvent (E)>

The content of the solvent (E) in the resist composition is usually 90%by mass or more and 99.9% by mass or less, preferably 92% by mass ormore and 99% by mass or less, and more preferably 94% by mass or moreand 99% by mass or less. The content of the solvent (E) can be measured,for example, by a known analysis means such as liquid chromatography orgas chromatography.

Examples of the solvent (E) include glycol ether esters such asethylcellosolve acetate, methylcellosolve acetate and propylene glycolmonomethyl ether acetate; glycol ethers such as propylene glycolmonomethyl ether; esters such as ethyl lactate, butyl acetate, amylacetate and ethyl pyruvate; ketones such as acetone, methyl isobutylketone, 2-heptanone and cyclohexanone; and cyclic esters such asγ-butyrolactone. The solvent (E) may be used alone, or two or moresolvents may be used.

<Quencher (C)>

Examples of the quencher (C) include a salt generating an acid having anacidity lower than that of an acid generated from an acid generator (B),and a basic nitrogen-containing organic compound. The content of thequencher (C) is preferably about 0.01 to 15% by mass, more preferablyabout 0.01 to 10% by mass, still more preferably about 0.1 to 8% bymass, and yet more preferably about 0.1 to 7% by mass, based on theamount of the solid component of the resist composition.

<Salt Generating Acid Having Acidity Lower than that of Acid Generatedfrom Acid Generator>

The acidity in a salt generating an acid having an acidity lower thanthat of an acid generated from the acid generator (B) is indicated bythe acid dissociation constant (pKa). Regarding the salt generating anacid having an acidity lower than that of an acid generated from theacid generator (B), the acid dissociation constant of an acid generatedfrom the salt usually meets the following inequality: −3<pKa, preferably−1<pKa<7, and more preferably 0<pKa<5.

Examples of the salt generating an acid having an acidity lower thanthat of an acid generated from the acid generator (B) include saltsrepresented by the following formulas, a salt represented by formula (D)mentioned in JP 2015-147926 A (hereinafter sometimes referred to as“weak acid inner salt (D)”), and salts mentioned in JP 2012-229206 A, JP2012-6908 A, JP 2012-72109 A, JP 2011-39502 A and JP 2011-191745 A. Thesalt generating an acid having an acidity lower than that of an acidgenerated from the acid generator (B) is preferably a salt generating acarboxylic acid having an acidity lower than that of an acid generatedfrom the acid generator (B) (salt having a carboxylic acid anion), morepreferably a weak acid inner salt (D), and still more preferably a weakacid inner salt (D).

The weak acid inner salt (D) is preferably a diphenyliodonium salthaving an iodonium cation to which two phenyl groups are bonded, and acarboxy anion substituted with at least one phenyl group of two phenylgroups bonded to the iodonium cation, and examples thereof include asalt represented by the following formula:

wherein, in formula (D),

R^(D1) and R^(D2) each independently represent a hydrocarbon grouphaving 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, anitro group or a halogen atom, and

m′ and n′ each independently represent an integer of 0 to 4, and when m′is 2 or more, a plurality of R^(D1) may be the same or different, andwhen n′ is 2 or more, a plurality of R^(D2) may be the same ordifferent.

Examples of the hydrocarbon group as for R^(D1) and R^(D2) include achain hydrocarbon group, an alicyclic hydrocarbon group, an aromatichydrocarbon group, and a group formed by combining these groups.

Examples of the chain hydrocarbon group include alkyl groups such as amethyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, an isobutyl group, a tert-butyl group, a pentyl group, ahexyl group, a nonyl group and the like.

The alicyclic hydrocarbon group may be either monocyclic or polycyclic,or may be either saturated or unsaturated. Examples thereof includecycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a cyclononyl group and acyclododecyl group, a norbornyl group, an adamantyl group and the like.

Examples of the aromatic hydrocarbon group include aryl groups such as aphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-methylphenylgroup, a 3-methylphenyl group, a 4-methylphenyl group, a 4-ethylphenylgroup, a 4-propylphenyl group, a 4-isopropylphenyl group, a4-butylphenyl group, a 4-t-butylphenyl group, a 4-hexylphenyl group, a4-cyclohexylphenyl group, an anthryl group, a p-adamantylphenyl group, atolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenylgroup, a phenanthryl group, a 2,6-diethylphenyl group and a2-methyl-6-ethylphenyl.

Examples of the group formed by combining these groups include analkyl-cycloalkyl group, a cycloalkyl-alkyl group, an aralkyl group(e.g., a phenylmethyl group, a 1-phenylethyl group, a 2-phenylethylgroup, a 1-phenyl-1-propyl group, a 1-phenyl-2-propyl group, a2-phenyl-2-propyl group, a 3-phenyl-1-propyl group, a 4-phenyl-1-butylgroup, a 5-phenyl-1-pentyl group, a 6-phenyl-1-hexyl group, etc.) andthe like.

Examples of the alkoxy group include a methoxy group, an ethoxy groupand the like.

Examples of the acyl group include an acetyl group, a propanoyl group, abenzoyl group, a cyclohexanecarbonyl group and the like.

Examples of the acyloxy group include a group obtained by bonding an oxygroup (—O—) to the above acyl group.

Examples of the alkoxycarbonyl group include a group obtained by bondinga carbonyl group (—CO—) to the above alkoxy group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom and the like.

Preferably, R^(D1) and R^(D2) each independently represent an alkylgroup having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl grouphaving 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms,an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group or ahalogen atom.

Preferably, m‘ and n’ are each independently an integer of 0 to 2, andmore preferably 0, and when m′ is 2 or more, a plurality of R^(D1) maybe the same or different, and when n′ is 2 or more, a plurality ofR^(D2) may be the same or different.

More specifically, the following salts are exemplified.

Examples of the basic nitrogen-containing organic compound include amineand an ammonium salt. Examples of the amine include an aliphatic amineand an aromatic amine. Examples of the aliphatic amine include a primaryamine, a secondary amine and a tertiary amine.

Examples of the amine include 1-naphthylamine, 2-naphthylamine, aniline,diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline,N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine,heptylamine, octylamine, nonylamine, decylamine, dibutylamine,dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine,didecylamine, triethylamine, trimethylamine, tripropylamine,tributylamine, tripentylamine, trihexylamine, triheptylamine,trioctylamine, trinonylamine, tridecylamine, methyldibutylamine,methyldipentylamine, methyldihexylamine, methyldicyclohexylamine,methyldiheptylamine, methyldioctylamine, methyldinonylamine,methyldidecylamine, ethyldibutylamine, ethyldipentylamine,ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine,ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine,tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine,ethylenediamine, tetramethylenediamine, hexamethylenediamine,4,4′-diamino-1,2-diphenylethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′-diethyldiphenylmethane, 2,2′-methylenebisaniline,imidazole, 4-methylimidazole, pyridine, 4-methylpyridine,1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane,1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene,1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane,di(2-pyridyl)ketone, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide,2,2′-dipyridylamine, 2,2′-dipicolylamine, bipyridine and the like,preferably an aromatic amine such as diisopropylaniline, and morepreferably 2,6-diisopropylaniline.

Examples of the ammonium salt include tetramethylammonium hydroxide,tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide,tetrahexylammonium hydroxide, tetraoctylammonium hydroxide,phenyltrimethylammonium hydroxide,3-(trifluoromethyl)phenyltrimethylammonium hydroxide,tetra-n-butylammonium salicylate and choline.

<Other Components>

The resist composition of the present disclosure may also includecomponents other than the components mentioned above (hereinaftersometimes referred to as “other components (F)”). The other components(F) are not particularly limited and it is possible to use variousadditives known in the resist field, for example, sensitizers,dissolution inhibitors, surfactants, stabilizers and dyes.

<Preparation of Resist Composition>

The resist composition of the present disclosure can be prepared bymixing a carboxylate represented by formula (I) or a resin including astructural unit represented by formula (I-1), and if necessary, a resin(A), an acid generator (B), resins other than the resin (A), a solvent(E), a quencher (C) and other components (F). The order of mixing thesecomponents is any order and is not particularly limited. It is possibleto select, as the temperature during mixing, appropriate temperaturefrom 10 to 40° C., according to the type of the resin, the solubility inthe solvent (E) of the resin and the like. It is possible to select, asthe mixing time, appropriate time from 0.5 to 24 hours according to themixing temperature. The mixing means is not particularly limited and itis possible to use mixing with stirring.

After mixing the respective components, the mixture is preferablyfiltered through a filter having a pore diameter of about 0.003 to 0.2μm.

<Method for Producing Resist Pattern>

The method for producing a resist pattern of the present disclosureinclude:

(1) a step of applying the resist composition of the present disclosureon a substrate,(2) a step of drying the applied composition to form a compositionlayer,(3) a step of exposing the composition layer,(4) a step of heating the exposed composition layer, and(5) a step of developing the heated composition layer.

The resist composition can be usually applied on a substrate using aconventionally used apparatus, such as a spin coater. Examples of thesubstrate include inorganic substrates such as a silicon wafer, andorganic substrates in which a resist film is formed on the surface.Before applying the resist composition, the substrate may be washed, andan organic antireflection film may be formed on the substrate.

The solvent is removed by drying the applied composition to form acomposition layer. Drying is performed by evaporating the solvent usinga heating device such as a hot plate (so-called “prebake”), or adecompression device. The heating temperature is preferably 50 to 200°C. and the heating time is preferably 10 to 180 seconds. The pressureduring drying under reduced pressure is preferably about 1 to 1.0×10⁵Pa.

The composition layer thus obtained is usually exposed using an aligner.The aligner may be a liquid immersion aligner. It is possible to use, asan exposure source, various exposure sources, for example, exposuresources capable of emitting laser beam in an ultraviolet region such asKrF excimer laser (wavelength of 248 nm), ArF excimer laser (wavelengthof 193 nm) and F₂ excimer laser (wavelength of 157 nm), an exposuresource capable of emitting harmonic laser beam in a far-ultraviolet orvacuum ultra violet region by wavelength-converting laser beam from asolid-state laser source (YAG or semiconductor laser), an exposuresource capable of emitting electron beam or extreme ultraviolet light(EUV) and the like. In the present specification, such exposure toradiation is sometimes collectively referred to as “exposure”. Theexposure is usually performed through a mask corresponding to a patternto be required. When electron beam is used as the exposure source,exposure may be performed by direct writing without using the mask.

The exposed composition layer is subjected to a heat treatment(so-called “post-exposure bake”) to promote the deprotection reaction inan acid-labile group. The heating temperature is usually about 50 to200° C., and preferably about 70 to 150° C. It is also possible toperform a chemical treatment (silylation) which adjusts thehydrophilicity or hydrophobicity of the resin on a surface side of thecomposition after heating. Before performing the development, the stepsof application of the resist composition, drying, exposure and heatingmay be repeatedly performed on the exposed composition layer.

The heated composition layer is usually developed with a developingsolution using a development apparatus. Examples of the developingmethod include a dipping method, a paddle method, a spraying method, adynamic dispensing method and the like. The developing temperature ispreferably, for example, 5 to 60° C. and the developing time ispreferably, for example, 5 to 300 seconds. It is possible to produce apositive resist pattern or negative resist pattern by selecting the typeof the developing solution as follows.

When the positive resist pattern is produced from the resist compositionof the present disclosure, an alkaline developing solution is used asthe developing solution. The alkaline developing solution may be variousaqueous alkaline solutions used in this field. Examples thereof includeaqueous solutions of tetramethylammonium hydroxide and(2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline).The surfactant may be contained in the alkaline developing solution.

It is preferable that the developed resist pattern is washed withultrapure water and then water remaining on the substrate and thepattern is removed.

When the negative resist pattern is produced from the resist compositionof the present disclosure, a developing solution containing an organicsolvent (hereinafter sometimes referred to as “organic developingsolution”) is used as the developing solution.

Examples of the organic solvent contained in the organic developingsolution include ketone solvents such as 2-hexanone and 2-heptanone;glycol ether ester solvents such as propylene glycol monomethyl etheracetate; ester solvents such as butyl acetate; glycol ether solventssuch as propylene glycol monomethyl ether; amide solvents such asN,N-dimethylacetamide; and aromatic hydrocarbon solvents such asanisole.

The content of the organic solvent in the organic developing solution ispreferably 90% by mass or more and 100% by mass or less, more preferably95% by mass or more and 100% by mass or less, and still more preferablythe organic developing solution is substantially composed of the organicsolvent.

Particularly, the organic developing solution is preferably a developingsolution containing butyl acetate and/or 2-heptanone. The total contentof butyl acetate and 2-heptanone in the organic developing solution ispreferably 50% by mass or more and 100% by mass or less, more preferably90% by mass or more and 100% by mass or less, and still more preferablythe organic developing solution is substantially composed of butylacetate and/or 2-heptanone.

The surfactant may be contained in the organic developing solution. Atrace amount of water may be contained in the organic developingsolution.

During development, the development may be stopped by replacing by asolvent with the type different from that of the organic developingsolution.

The developed resist pattern is preferably washed with a rinsingsolution. The rinsing solution is not particularly limited as long as itdoes not dissolve the resist pattern, and it is possible to use asolution containing an ordinary organic solvent which is preferably analcohol solvent or an ester solvent.

After washing, the rinsing solution remaining on the substrate and thepattern is preferably removed.

<Applications>

The resist composition of the present disclosure is suitable as a resistcomposition for exposure of KrF excimer laser, a resist composition forexposure of ArF excimer laser, a resist composition for exposure ofelectron beam (EB) or a resist composition for exposure of EUV,particularly a resist composition for exposure of electron beam (EB) ora resist composition for exposure of EUV, and the resist composition isuseful for fine processing of semiconductors.

EXAMPLES

The present disclosure will be described more specifically by way ofExamples. Percentages and parts expressing the contents or amounts usedin the Examples are by mass unless otherwise specified.

The weight-average molecular weight is a value determined by gelpermeation chromatography. Analysis conditions of gel permeationchromatography are as follows.

Column: TSKgel Multipore IIXL-M×3+guardcolumn (manufactured by TOSOHCORPORATION)

Eluent: tetrahydrofuran

Flow rate: 1.0 mL/min

Detector: RI detector

Column temperature: 40° C.

Injection amount: 100 μl

Molecular weight standards: polystyrene standard (manufactured by TOSOHCORPORATION)

Structures of compounds were confirmed by measuring a molecular ion peakusing mass spectrometry (LC is Model 1100, manufactured by AgilentTechnologies, Inc., and MASS is Model LC/MSD, manufactured by AgilentTechnologies, Inc.). The value of this molecular ion peak in thefollowing Examples is indicated by “MASS”.

Example 1: Synthesis of Salt Represented by Formula (I-1)

5.28 Parts of a compound represented by formula (I-1-a), 30 parts ofacetonitrile and 2.32 parts of silver oxide were mixed, followed bystirring at 23° C. for 4 hours and further filtration. To the filterresidue thus obtained, 20 parts of tert-butyl methyl ether was added,followed by stirring at 23° C. for 30 minutes and further filtration toobtain 5.86 parts of a salt represented by formula (I-1-b).

3.91 Parts of a salt represented by formula (I-1-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 5.82 parts of a saltrepresented by formula (I-1).

MASS (ESI (+) Spectrum): M⁺ 355.1

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 2: Synthesis of Salt Represented by Formula (I-190)

5.16 Parts of a salt represented by formula (I-190-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 7.01 parts of a saltrepresented by formula (1-190).

MASS (ESI (+) Spectrum): M⁺ 481.0

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 3: Synthesis of Salt Represented by Formula (I-192)

5.32 Parts of a compound represented by formula (I-192-a), 30 parts ofacetonitrile and 2.32 parts of silver oxide were mixed, followed bystirring at 23° C. for 4 hours and further filtration. To the filterresidue thus obtained, 20 parts of tert-butyl methyl ether was added,followed by stirring at 23° C. for 30 minutes and further filtration toobtain 5.61 parts of a salt represented by formula (I-192-b).

5.16 Parts of a salt represented by formula (I-190-c), 3.73 parts of asalt represented by formula (I-192-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 6.24 parts of a saltrepresented by formula (I-192).

MASS (ESI (+) Spectrum): M⁺ 481.0

MASS (ESI (−) Spectrum): M⁻ 265.1

Example 4: Synthesis of Salt Represented by Formula (I-194)

4.12 Parts of a compound represented by formula (I-194-a), 30 parts ofacetonitrile and 2.32 parts of silver oxide were mixed, followed bystirring at 23° C. for 4 hours and further filtration. To the filterresidue thus obtained, 20 parts of tert-butyl methyl ether was added,followed by stirring at 23° C. for 30 minutes and further filtration toobtain 4.31 parts of a salt represented by formula (I-194-b).

5.16 Parts of a salt represented by formula (I-190-c), 3.13 parts of asalt represented by formula (I-194-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 5.08 parts of a saltrepresented by formula (I-194).

MASS (ESI (+) Spectrum): M⁺ 481.0

MASS (ESI (−) Spectrum): M⁻ 205.1

Example 5: Synthesis of Salt Represented by Formula (I-946)

6.53 Parts of a salt represented by formula (I-946-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 8.02 parts of a saltrepresented by formula (1-946).

MASS (ESI (+) Spectrum): M⁺617.0

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 6: Synthesis of Salt Represented by Formula (I-1000)

6.17 Parts of a salt represented by formula (I-1000-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 7.43 parts of a saltrepresented by formula (I-1000).

MASS (ESI (+) Spectrum): M⁺ 581.0

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 7: Synthesis of Salt Represented by Formula (I-1189)

5.31 Parts of a salt represented by formula (I-1189-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 6.06 parts of a saltrepresented by formula (I-1189).

MASS (ESI (+) Spectrum): M⁺ 495.0

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 8: Synthesis of Salt Represented by Formula (I-1405)

5.16 Parts of a salt represented by formula (1-1405-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 7.68 parts of a saltrepresented by formula (I-1405).

MASS (ESI (+) Spectrum): M⁺ 636.9

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 9: Synthesis of Salt Represented by Formula (I-2482)

8.09 Parts of a salt represented by formula (I-2482-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 8.81 parts of a saltrepresented by formula (I-2482).

MASS (ESI (+) Spectrum): M⁺ 772.9

MASS (ESI (−) Spectrum): M⁻ 263.1

Example 10: Synthesis of Salt Represented by Formula (I-2509)

8.09 Parts of a salt represented by formula (I-2482-c), 3.71 parts of asalt represented by formula (I-1-b), 20 parts of methanol and 10 partsof ion-exchanged water were mixed, followed by stirring at 23° C. for 30minutes. To the mixture thus obtained, 0.44 part of potassium carbonatewas added, followed by stirring at 23° C. for 5 hours. To the reactionproduct thus obtained, 60 parts of chloroform and 10 parts ofion-exchanged water were added, and after stirring at 23° C. for 30minutes, the organic layer was isolated through separation. To theorganic layer thus obtained, 30 parts of ion-exchanged water was added,and after stirring at 23° C. for 30 minutes, the organic layer wasisolated through separation. This water washing operation was repeatedseven times. The organic layer thus obtained was concentrated and then30 parts of tert-butyl methyl ether was added to the concentratedresidue, and after stirring at 23° C. for 30 minutes, the supernatantwas removed, followed by concentration to obtain 8.81 parts of a saltrepresented by formula (I-2482).

MASS (ESI (+) Spectrum): M⁺ 772.9

MASS (ESI (−) Spectrum): M⁻ 263.1

Synthesis of Resin

Compounds (monomers) used in synthesis of a resin (A) are shown below.Hereinafter, these compounds are referred to as “monomer (a1-1-3)”according to the formula number.

Example 11 [Synthesis of Resin A1]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-1) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2):monomer (I-1)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin A1 having a weight-average molecular weight of about 5.5×10³ in ayield of 64%. This resin A1 has the following structural units.

Example 12 [Synthesis of Resin A2]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-190) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-190)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin A2 having a weight-average molecular weight of about 5.4×10³ in ayield of 60%. This resin A2 has the following structural units.

Example 13 [Synthesis of Resin A3]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-192) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-192)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin A3 having a weight-average molecular weight of about 5.6×10³ in ayield of 62%. This resin A3 has the following structural units.

Example 14 [Synthesis of Resin A4]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-194) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-194)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin A4 having a weight-average molecular weight of about 5.2×10³ in ayield of 66%. This resin A4 has the following structural units.

Example 15 [Synthesis of Resin A5]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-13) and a monomer (I-190) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-13): monomer (I-190)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution was added in theamount of 2.0 mass times the total mass of all monomers, followed bystirring for 12 hours and further isolation through separation. Theorganic layer thus recovered was poured into a large amount of n-heptaneto precipitate a resin, followed by filtration and recovery to obtain aresin A5 having a weight-average molecular weight of about 5.4×10³ in ayield of 58%. This resin A5 has the following structural units.

Example 16 [Synthesis of Resin A6]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-2) and a monomer (I-190) as monomers, these monomers weremixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-2): monomer (I-190)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution was added in theamount of 2.0 mass times the total mass of all monomers, followed bystirring for 12 hours and further isolation through separation. Theorganic layer thus recovered was poured into a large amount of n-heptaneto precipitate a resin, followed by filtration and recovery to obtain aresin A6 having a weight-average molecular weight of about 5.4×10³ in ayield of 78%. This resin A6 has the following structural units.

Example 17 [Synthesis of Resin A7]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-13) and a monomer (I-190) as monomers, these monomers weremixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-13): monomer (I-190)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A7 having a weight-average molecularweight of about 5.4×10³ in a yield of 70%. This resin A7 has thefollowing structural units.

Example 18 [Synthesis of Resin A8]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-19) and a monomer (I-190) as monomers, these monomers weremixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-19): monomer (I-190)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A8 having a weight-average molecularweight of about 5.3×10³ in a yield of 73%. This resin A8 has thefollowing structural units.

Example 19 [Synthesis of Resin A9]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-20) and a monomer (I-190) as monomers, these monomers weremixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-20): monomer (I-190)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A9 having a weight-average molecularweight of about 5.5×10³ in a yield of 64%. This resin A9 has thefollowing structural units.

Example 20 [Synthesis of Resin A10]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-946) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-946)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin A10 having a weight-average molecular weight of about 5.4×10³ in ayield of 63%. This resin A10 has the following structural units.

Example 21 [Synthesis of Resin A11]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-1000) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-1000)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A11 having a weight-average molecularweight of about 5.6×10³ in a yield of 61%. This resin A11 has thefollowing structural units.

Example 22 [Synthesis of Resin A12]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-1189) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-1189)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A12 having a weight-average molecularweight of about 5.3×10³ in a yield of 66%. This resin A12 has thefollowing structural units.

Example 23 [Synthesis of Resin A13]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-1405) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-1405)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A13 having a weight-average molecularweight of about 5.4×10³ in a yield of 62%. This resin A13 has thefollowing structural units.

Example 24 [Synthesis of Resin A14]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-13) and a monomer (I-1189) asmonomers, these monomers were mixed in a molar ratio of 20:35:3:12:25:5[monomer (a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer(a3-4-2):monomer (a1-4-13): monomer (I-1189)], and then this monomermixture was mixed with methyl isobutyl ketone in the amount of 1.5 masstimes the total mass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A14 having a weight-average molecularweight of about 5.3×10³ in a yield of 61%. This resin A14 has thefollowing structural units.

Example 25 [Synthesis of Resin A15]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-2) and a monomer (I-1189) as monomers, these monomers weremixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-2): monomer (I-1189)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A15 having a weight-average molecularweight of about 5.5×10³ in a yield of 61%. This resin A15 has thefollowing structural units.

Example 26 [Synthesis of Resin A16]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-13) and a monomer (I-1189) as monomers, these monomerswere mixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-2): monomer (I-1189)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A16 having a weight-average molecularweight of about 5.3×10³ in a yield of 75%. This resin A16 has thefollowing structural units.

Example 27 [Synthesis of Resin A17]

Using a monomer (a1-2-6), a monomer (a2-1-3), a monomer (a3-4-2), amonomer (a1-4-19) and a monomer (I-1189) as monomers, these monomerswere mixed in a molar ratio of 55:3:12:25:5 [monomer (a1-2-6):monomer(a2-1-3):monomer (a3-4-2):monomer (a1-4-2): monomer (I-1189)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A17 having a weight-average molecularweight of about 5.3×10³ in a yield of 79%. This resin A17 has thefollowing structural units.

Example 28 [Synthesis of Resin A18]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-2482) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-2482)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A18 having a weight-average molecularweight of about 5.6×10³ in a yield of 61%. This resin A18 has thefollowing structural units.

Example 29 [Synthesis of Resin A19]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (I-2509) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2): monomer (I-2509)], and then this monomer mixture was mixedwith methyl isobutyl ketone in the amount of 1.5 mass times the totalmass of all monomers. To the mixture thus obtained,azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) asinitiators were added in the amounts of 1.2 mol % and 3.6 mol % based onthe amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin A19 having a weight-average molecularweight of about 5.3×10³ in a yield of 62%. This resin A19 has thefollowing structural units.

Synthesis Example 1 [Synthesis of Resin AX1]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2), a monomer (a1-4-2) and a monomer (AX-1) as monomers,these monomers were mixed in a molar ratio of 20:35:3:12:25:5 [monomer(a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer(a1-4-2):monomer (AX-1)], and then this monomer mixture was mixed withmethyl isobutyl ketone in the amount of 1.5 mass times the total mass ofall monomers. To the mixture thus obtained, azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) as initiators were added in theamounts of 1.2 mol % and 3.6 mol % based on the amount of all monomers,followed by heating at 73° C. for about 5 hours. Thereafter, to thepolymerization reaction solution thus obtained, an aqueousp-toluenesulfonic acid solution (2.5% by weight) was added in the amountof 2.0 mass times the total mass of all monomers, followed by stirringfor 12 hours and further isolation through separation. The organic layerthus recovered was poured into a large amount of n-heptane toprecipitate a resin, followed by filtration and recovery to obtain aresin AX1 having a weight-average molecular weight of about 5.5×10³ in ayield of 66%. This resin AX1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin AA1]

Using a monomer (a1-1-3), a monomer (a1-2-6), a monomer (a2-1-3), amonomer (a3-4-2) and a monomer (a1-4-2) as monomers, these monomers weremixed in a molar ratio of 20:35:3:15:27 [monomer (a1-1-3):monomer(a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer (a1-4-2)], and thenthis monomer mixture was mixed with methyl isobutyl ketone in the amountof 1.5 mass times the total mass of all monomers. To the mixture thusobtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)as initiators were added in the amounts of 1.2 mol % and 3.6 mol % basedon the amount of all monomers, followed by heating at 73° C. for about 5hours. Thereafter, to the polymerization reaction solution thusobtained, an aqueous p-toluenesulfonic acid solution (2.5% by weight)was added in the amount of 2.0 mass times the total mass of allmonomers, followed by stirring for 12 hours and further isolationthrough separation. The organic layer thus recovered was poured into alarge amount of n-heptane to precipitate a resin, followed by filtrationand recovery to obtain a resin AA1 having a weight-average molecularweight of about 5.5×10³ in a yield of 68%. This resin AA1 has thefollowing structural units.

<Preparation of Resist Composition>

As shown in Table 2, the following components were mixed and the mixturethus obtained was filtered through a fluororesin filter having a porediameter of 0.2 μm to prepare resist compositions.

TABLE 2 Acid Resist generator Carboxylate Quencher composition Resin (B)(I) (C) PB/PEB Composition 1 AA1 = B1-25 = I-190 = — 100° C./130° C. 10parts 2.5 parts 0.4 part Composition 2 AA1 = B1-25 = I-1 = — 100°C./130° C. 10 parts 2.5 parts 0.4 part Composition 3 AA1 = B1-25 = I-192= — 100° C./130° C. 10 parts 2.5 parts 0.4 part Composition 4 AA1 =B1-25 = I-194 = — 100° C./130° C. 10 parts 2.5 parts 0.4 partComposition 5 A2 = B1-25 = — C1 = 100° C./130° C. 10 parts 2.5 parts 0.1part Composition 6 A1 = B1-25 = — C1 = 100° C./130° C. 10 parts 2.5parts 0.1 part Composition 7 A2 = B1-25 = I-190 = — 100° C./130° C. 10parts 2.5 parts 0.1 part Composition 8 A1 = B1-25 = I-1 = — 100° C./130°C. 10 parts 2.5 parts 0.1 part Composition 9 A2 = B1-25 = — — 100°C./130° C. 10 parts 2.5 parts Composition 10 A1 = B1-25 = — — 100°C./130° C. 10 parts 2.5 parts Composition 11 A3 = B1-25 = — C1 = 100°C./130° C. 10 parts 2.5 parts 0.1 part Composition 12 A4 = B1-25 = — C1= 100° C./130° C. 10 parts 2.5 parts 0.1 part Composition 13 A5 = B1-25= — C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 part Composition 14 A6 =B1-25 = — C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 part Composition15 A7 = B1-25 = — C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 partComposition 16 A8 = B1-25 = — C1 = 100° C./130° C. 10 parts 2.5 parts0.1 part Composition 17 A9 = B1-25 =   C1 = 100° C./130° C. 10 parts 2.5parts 0.1 part Composition 18 AA1 = B1-25 = I-946 =   100° C./130° C. 10parts 2.5 parts 0.4 part Composition 19 A10 = B1-25 =   C1 = 100°C./130° C. 10 parts 2.5 parts 0.1 part Composition 20 A10 = B1-25 =I-946 =   100° C./130° C. 10 parts 2.5 parts 0.1 part Composition 21 A10= B1-25 =     100° C./130° C. 10 parts 2.5 parts Composition 22 AA1 =B1-25 = I-1000 =   100° C./130° C. 10 parts 2.5 parts 0.4 partComposition 23 A11 = B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts0.1 part Composition 24 A11 = B1-25 = I-1000 =   100° C./130° C. 10parts 2.5 parts 0.1 part Composition 25 A11 = B1-25 =     100° C./130°C. 10 parts 2.5 parts Composition 26 AA1= B1-25 = I-1189 =   100°C./130° C. 10 parts 2.5 parts 0.4parts Composition 27 AA1= B1-25 =I-1405 =   100° C./130° C. 10 parts 2.5 parts 0.4parts Composition 28A12 = B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 partsComposition 29 A13 = B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts0.1 parts Composition 30 A12 = B1-25 = I-1189 =   100° C./130° C. 10parts 2.5 parts 0.1 parts Composition 31 A13 = B1-25 = I-1405 =   100°C./130° C. 10 parts 2.5 parts 0.1 parts Composition 32 A12 = B1-25 =    100° C./130° C. 10 parts 2.5 parts Composition 33 A13 = B1-25 =     100°C./130° C. 10 parts 2.5 parts Composition 34 A14 = B1-25 =   C1 = 100°C./130° C. 10 parts 2.5 parts 0.1 parts Composition 35 A15 = B1-25 =  C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 parts Composition 36 A16 =B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 parts Composition37 A17 = B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 partsComposition 38 AA1 = B1-25 = I-2482 =   100° C./130° C. 10 parts 2.5parts 0.4 parts Composition 39 A18 = B1-25 =   C1 = 100° C./130° C. 10parts 2.5 parts 0.1 parts Composition 40 A19 = B1-25 = I-2482 =   100°C./130° C. 10 parts 2.5 parts 0.1 parts Composition 41 A18 = B1-25 =    100° C./130° C. 10 parts 2.5 parts Composition 42 AA1 = B1-25 = I-2509 =  100° C./130° C. 10 parts 2.5 parts 0.4 parts Composition 43 A19 =B1-25 =   C1 = 100° C./130° C. 10 parts 2.5 parts 0.1 parts Composition44 A19 = B1-25 = I-2509 =   100° C./130° C. 10 parts 2.5 parts 0.1 partsComposition 45 A19 = B1-25 =     100° C./130° C. 10 parts 2.5 partsComparative AA1 = B1-25 =   IX-1 = 100° C./130° C. Composition 1 10parts 2.5 parts 0.4 part Comparative AX1 = B1-25 =   C1 = 100° C./130°C. Composition 2 10 parts 2.5 parts 0.1 part Comparative AX1 = B1-25 =  IX-1 = 100° C./130° C. Composition 3 10 parts 2.5 parts 0.1 partComparative AX1 = B1-25 =     100° C./130° C. Composition 4 10 parts 2.5parts

<Resin>

A1 to A19, AA1, AX1: Resin A1 to Resin A11, Resin AA1, Resin AX1

<Acid Generator (B)>

B1-25: Salt represented by Formula (B1-25);

synthesized by the method mentioned in JP 2011-126869 A

<Carboxylate (I)>

I-1: Salt represented by Formula (I-1)

I-190: Salt represented by Formula (I-190)

I-192: Salt represented by Formula (I-192)

I-194: Salt represented by Formula (I-194)

I-946: Salt represented by Formula (I-946)

I-1000: Salt represented by Formula (I-1000)

I-617: Salt represented by Formula (I-1189)

I-618: Salt represented by Formula (I-1405)

I-620: Salt represented by Formula (I-2482)

I-730: Salt represented by Formula (I-2509)

<Quencher (C)>

C1: synthesized by the method mentioned in JP 2011-39502 A

IX-1:synthesized by the method mentioned in JP 2011-037834 A

<Solvent>

Propylene glycol monomethyl ether acetate 400 part Propylene glycolmonomethyl ether 100 part γ-Butyrolactone(Evaluation of Exposure of Resist Composition with Electron Beam)

Each 6 inch-diameter silicon wafer was treated with hexamethyldisilazaneon a direct hot plate at 90° C. for 60 seconds. A resist composition wasspin-coated on the silicon wafer in such a manner that the thickness ofthe composition layer became 0.04 μm. Then, the coated silicon wafer wasprebaked on the direct hot plate at the temperature shown in the column“PB” of Table 2 for 60 seconds to form a composition layer. Using anelectron-beam direct-write system (“ELS-F125 125 keV”, manufactured byELIONIX INC.), line and space patterns (pitch of 60 nm/line width of 30nm) were directly written on the composition layer formed on the waferwere directly written on the composition layer formed on the wafer afterdevelopment while changing the exposure dose stepwise.

After exposure, post-exposure baking was performed on the hot plate atthe temperature shown in the column “PEB” of Table 2 for 60 second.Next, the composition layer on this silicon wafer was developed withbutyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as adeveloper at 23° C. for 20 seconds using the dynamic dispensing methodto obtain resist patterns.

The thus obtained resist patterns (line and space patterns) wereobserved by a scanning electron microscope, and effective sensitivitywas expressed as the exposure dose at which a ratio of the line width tothe space width of the line and space patterns with a pitch of 60 nmbecame 1:1 after exposure.

Evaluation of Line Edge Roughness (LER): Line edge roughness wasdetermined by measuring a roughness width of the irregularity in wallsurface of resist pattern produced by the effective sensitivity using ascanning electron microscope. The results are shown in Table 3.

TABLE 3 Resist composition LER Example 30 Composition 1 3.69 Example 31Composition 2 3.79 Example 32 Composition 3 3.67 Example 33 Composition4 3.70 Example 34 Composition 5 3.51 Example 35 Composition 6 3.66Example 36 Composition 7 3.57 Example 37 Composition 8 3.76 Example 38Composition 9 3.68 Example 39 Composition 10 3.85 Example 40 Composition11 3.50 Example 41 Composition 12 3.53 Example 42 Composition 13 3.40Example 43 Composition 14 3.53 Example 44 Composition 15 3.42 Example 45Composition 16 3.46 Example 46 Composition 17 3.60 Example 47Composition 18 3.60 Example 48 Composition 19 3.41 Example 49Composition 20 3.46 Example 50 Composition 21 3.62 Example 51Composition 22 3.62 Example 52 Composition 23 3.44 Example 53Composition 24 3.49 Example 54 Composition 25 3.65 Example 55Composition 26 3.62 Example 56 Composition 27 3.53 Example 57Composition 28 3.51 Example 58 Composition 29 3.40 Example 59Composition 30 3.46 Example 60 Composition 31 3.35 Example 61Composition 32 3.57 Example 62 Composition 33 3.48 Example 63Composition 34 3.39 Example 64 Composition 35 3.52 Example 65Composition 36 3.40 Example 66 Composition 37 3.45 Example 67Composition 38 3.44 Example 68 Composition 39 3.33 Example 69Composition 40 3.35 Example 70 Composition 41 3.39 Example 71Composition 42 3.45 Example 72 Composition 43 3.34 Example 73Composition 44 3.36 Example 74 Composition 45 3.40 Comparative Example 1Comparative Composition 1 3.98 Comparative Example 2 ComparativeComposition 2 3.86 Comparative Example 3 Comparative Composition 3 3.93Comparative Example 4 Comparative Composition 4 4.02

As compared with Comparative Compositions 1 to 4, Compositions 1 to 45exhibited satisfactory line edge roughness (LER).

A resist composition including a carboxylate of the present disclosureis capable of obtaining a resist pattern with satisfactory line edgeroughness (LER), and is therefore useful for fine processing ofsemiconductors and is industrially extremely useful.

What claimed is:
 1. A carboxylate represented by formula (I):

wherein, in formula (I), R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ each independentlyrepresent a halogen atom, a haloalkyl group having 1 to 12 carbon atomsor a hydrocarbon group having 1 to 18 carbon atoms, wherein each of thehydrocarbon group may have a substituent, and a —CH₂— included in eachof the haloalkyl group and the hydrocarbon group may be replaced by —O—,—CO—, —S— or —SO₂—, A¹, A² and A³ each independently represent ahydrocarbon group having 1 to 20 carbon atoms, wherein each of thehydrocarbon group may have a substituent, and a —CH₂-included in each ofthe hydrocarbon group may be replaced by —O—, —CO—, —S— or —SO₂—, m1represents an integer of 1 to 5, and when m1 is 2 or more, a pluralityof groups in parentheses may be the same or different from each other,m2 represents an integer of 0 to 5, and when m2 is 2 or more, aplurality of groups in parentheses may be the same or different fromeach other, m3 represents an integer of 0 to 5, and when m3 is 2 ormore, a plurality of groups in parentheses may be the same or differentfrom each other, m4 represents an integer of 0 to 5, and when m4 is 2 ormore, a plurality of R⁴ may be the same or different from each other, m5represents an integer of 0 to 5, and when m5 is 2 or more, a pluralityof R⁵ may be the same or different from each other, m6 represents aninteger of 0 to 5, and when m6 is 2 or more, a plurality of R⁶ may bethe same or different from each other, m7 represents an integer of 0 to4, and when m7 is 2 or more, a plurality of R⁷ may be the same ordifferent from each other, m8 represents an integer of 0 to 5, and whenm8 is 2 or more, a plurality of R⁸ may be the same or different fromeach other, m9 represents an integer of 0 to 5, and when m9 is 2 ormore, a plurality of R⁹ may be the same or different from each other, inwhich 1≤m1+m7≤5, 0≤m2+m8≤5, 0≤m3+m9≤5, X⁰ represents a single bond or ahydrocarbon group having 1 to 72 carbon atoms which may have asubstituent, and a —CH₂— included in the hydrocarbon group may bereplaced by —O—, —S—, —CO— or —SO₂—, Ph represents a phenylene groupwhich may have a substituent, Ax represents a single bond, an etherbond, an ester bond or a carbonic acid ester bond, Ay represents asingle bond, an ether bond, an ester bond or a carbonic acid esterbond, * represents a bonding site to carbon atoms to which —R^(bb1) isbonded, ** represents a bonding site to L¹⁰, and L¹⁰ represents a singlebond or a hydrocarbon group having 1 to 36 carbon atoms which may have asubstituent, and a —CH₂— included in the hydrocarbon group may bereplaced by —O—, —S—, —SO₂— or —CO—.
 2. The carboxylate according toclaim 1, wherein A¹ is ***—X⁰¹-L⁰¹- or ***-L⁰¹-X⁰¹—, A² is ***—X⁰²-L⁰²-or ***-L⁰²-X⁰²—, A³ is ***—X⁰³-L⁰³- or ***-L⁰³-X⁰³—, X⁰¹, X⁰² and X⁰³each independently represent —O—, —CO—, —S— or —SO₂—, L⁰¹, L⁰² and L⁰³each independently represent a single bond or a hydrocarbon group having1 to 18 carbon atoms, and each *** represents a bonding site to thebenzene ring to which S⁺ is bonded.
 3. The carboxylate according toclaim 2, wherein X⁰¹, X⁰² and X⁰³ are oxygen atoms.
 4. The carboxylateaccording to claim 2, wherein L⁰¹, L⁰² and L⁰³ are each independently asingle bond or an alkanediyl group having 1 to 6 carbon atoms.
 5. Thecarboxylate according to claim 1, wherein R⁴, R³ and R⁶ are eachindependently a fluorine atom, an iodine atom or a perfluoroalkyl grouphaving 1 to 4 carbon atoms.
 6. The carboxylate according to claim 1,wherein X⁰ is an aliphatic hydrocarbon group having 1 to 72 carbon atomswhich may have a substituent, and a —CH₂— included in the aliphatichydrocarbon group may be replaced by —O—, —S—, —CO— or —SO₂— or anaromatic hydrocarbon group having 6 to 36 carbon atoms which may have asubstituent.
 7. The carboxylate according to claim 6, wherein X⁰includes an alicyclic hydrocarbon group having 3 to 36 carbon atomswhich may have a fluorine atom, a perfluoroalkyl group having 1 to 4carbon atoms or a hydroxy group and a —CH₂-included in the alicyclichydrocarbon group may be replaced by —O—, —S—, —CO— or —SO₂—, a groupobtained by combining an alicyclic hydrocarbon group having 3 to 36carbon atoms with a chain hydrocarbon group having 1 to 18 carbon atoms,a —CH₂— included in the alicyclic hydrocarbon group may be replaced by—O—, —S—, —CO— or —SO₂—, a —CH₂— included in the chain hydrocarbon groupmay be replaced by —O— or —CO—, and the alicyclic hydrocarbon group andthe chain hydrocarbon group may have a fluorine atom, a perfluoroalkylgroup having 1 to 4 carbon atoms or a hydroxy group, or an aromatichydrocarbon group having 6 to 36 carbon atoms which may have a fluorineatom, a perfluoroalkyl group having 1 to 4 carbon atoms or a hydroxygroup.
 8. The carboxylate according to claim 6, wherein X⁰ includes thealicyclic hydrocarbon group, and the alicyclic hydrocarbon group is acycloalkanediyl group having 5 or 6 carbon atoms, an adamandiyl group, anorbornanediyl group, or a polycyclic alicyclic hydrocarbon group inwhich a cycloalkanediyl group having 5 or 6 carbon atoms and anadamantanediyl group are spiro-bonded, a —CH₂— included in theadamantanediyl group, the norbornanediyl group and the cycloalkanediylgroup may be replaced by —O— or —CO—, a —CH₂—CH₂— included in theadamantanediyl group and the norbornanediyl group may be replaced by—O—CO—, and the cycloalkanediyl group may be an acetal ring.
 9. Thecarboxylate according to claim 1, wherein X¹⁰ is a single bond or agroup represented by any one of formula (X¹-1), formula (X¹-2′) toformula (X¹-7′) and formula (X¹-8):

wherein, in formula (X1-1), formula (X1-2′) to formula (X1-7′) andformula (X1-8), * and ** are bonding sites, and ** represents a bondingsite to L¹⁰, Rx represents a halogen atom, a hydroxy group, an alkylfluoride group having 1 to 6 carbon atoms, an alkyl group having 1 to 18carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and mxrepresents an integer of 0 to
 4. 10. The carboxylate according to claim1, wherein L¹⁰ is a single bond or an alkanediyl group having 1 to 4carbon atoms, a —CH₂— included in the alkanediyl group may be replacedby —O— or —CO—.
 11. The carboxylate according to claim 7, wherein X⁰ isa phenylene group which may have a substituent, and L¹⁰ is a singlebond, and X¹⁰ is a single bond or a *—CO—O—**, and * and ** are bondingsites, and ** represents a bonding site to L¹⁰.
 12. A resin comprising astructural unit derived from the carboxylate according to claim
 1. 13. Aresist composition comprising the carboxylate according to claim 1 or aresin including a structural unit derived from the carboxylate accordingto claim
 1. 14. The resist composition according to claim 13, furthercomprising; a resin including a structural unit having an acid labilegroup, wherein the acid-labile group includes at least one selected fromthe group consisting of a structural unit represented by formula (a1-0),a structural unit represented by formula (a1-1) and a structural unitrepresented by formula (a1-2):

wherein, in formula (a1-0), formula (a1-1) and formula (a1-2), L^(a01),L^(a1) and L^(a2) each independently represent —O— or*—O—(CH₂)_(k1)—CO—O—, k1 represents an integer of 1 to 7, and *represents a bonding site to —CO—, R^(a01), R^(a4) and R^(a5) eachindependently represent a hydrogen atom, a halogen atom, or an alkylgroup having 1 to 6 carbon atoms which may have a halogen atom, R^(a02),R^(a03) and R^(a04) each independently represent an alkyl group having 1to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbonatoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or agroup obtained by combining these groups, R^(a6) and R^(a7) eachindependently represent an alkyl group having 1 to 8 carbon atoms, analkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon grouphaving 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to18 carbon atoms, or a group formed by combining these groups, m1represents an integer of 0 to 14, n1 represents an integer of 0 to 10,and n1′ represents an integer of 0 to
 3. 15. The resist compositionaccording to claim 13, further comprising: a resin including astructural unit represented by formula (a2-A):

wherein, in formula (a2-A), R^(a50) represents a hydrogen atom, ahalogen atom, or an alkyl group having 1 to 6 carbon atoms which mayhave a halogen atom, R^(a51) represents a halogen atom, a hydroxy group,an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, analkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl grouphaving 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4carbon atoms, an acryloyloxy group or a methacryloyloxy group, A^(a50)represents a single bond or *—X^(a5)-(A^(a52)-X^(a52)) and * representsa bond to carbon atoms to which —R^(a50) is bonded, A^(a52) representsan alkanediyl group having 1 to 6 carbon atoms, X^(a51) and X^(a52) eachindependently represent —O—, —CO—O— or —O—CO—, nb represents 0 or 1, andmb represents an integer of 0 to 4, and when mb is an integer of 2 ormore, a plurality of R^(a51) may be the same or different from eachother.
 16. The resist composition according to claim 13, furthercomprising: a acid generator including a salt represented by formula(B1):

wherein, in formula (B1), Q^(b1) and Q^(b2) each independently representa hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6carbon atoms or an alkyl group having 1 to 6 carbon atoms, L^(b1)represents a divalent saturated hydrocarbon group having 1 to 24 carbonatoms, a —CH₂— included in the divalent saturated hydrocarbon group maybe replaced by —O— or —CO—, and a hydrogen atom included in the divalentsaturated hydrocarbon group may be substituted with a fluorine atom or ahydroxy group, Y represents a methyl group which may have a substituentor an alicyclic hydrocarbon group having 3 to 24 carbon atoms which mayhave a substituent, and a —CH₂-included in the alicyclic hydrocarbongroup may be replaced by —O—, —S—, —SO₂— or —CO—, and Z⁺ represents anorganic cation.
 17. A resist composition comprising the carboxylateaccording to claim 1 and a resin including a structural unit having anacid labile group.
 18. A resist composition comprising a resin includinga structural unit derived from the carboxylate according to claim 1 anda structural unit having an acid labile group.
 19. A resist compositioncomprising the carboxylate according to claim 1 and a resin including astructural unit derived from the carboxylate according to claim
 1. 20. Amethod for producing a resist pattern, which comprises: (1) a step ofapplying the resist composition according to claim 13 on a substrate,(2) a step of drying the applied composition to form a compositionlayer, (3) a step of exposing the composition layer, (4) a step ofheating the exposed composition layer, and (5) a step of developing theheated composition layer.